What exactly merits the "fraud" part of the title? And why is there "more" of it?

The fraud Meg is that the Church held to a flat Earth at one time. 

It is that and more.  The claim that Medieval Catholics believed the earth was flat is usually accompanied, either explicitly or implicitly, by the idea that Catholics are stupid, superstitious and irrational.  

While actual historians understand how untrue the claim is, it is still spread to children in public schools.  It is one of the clearest examples of anti-Catholicism in our society.  This anti-Catholic propaganda is accepted by many, probably most, people as if it were some sort of neutral factual education.  

The article did a nice job of showing how the claim has nothing to do with truth and is all about attacking the Church.  The author even mentioned that this is a general problem with the way that "history" is commonly taught, not simply confined to this one case.  It is a good reminder that the world hates the Catholic Church.  

Your title gives the impression that those who believe in a flat earth are perpetuating a fraud.

Anyone who claims that there is anything inherently Catholic about believing the earth is flat or that this is the historical belief of Catholics (which you have done) is perpetrating a fraud.

If people think there is some sort of scientific basis to question the sphericity of the earth, it may be legitimate to do so, but false claims about Church history mean that one is supporting the enemies of the Church in their attack on her.

The condemnation of the globe by the Church is clear from the Fathers of the Church.

This is clearly untrue, although it is likely that TomGubbinsKimmage is not lying but was himself deceived.  I have seen sites that make this claim and give a few cherry-picked or out of context quotes to back it up.  Some Fathers believed the earth was flat, some believed it a sphere.  The eventual consensus adopted by the Church was the position of St. Augustine and St. Basil that Scripture is silent on the shape of the earth, it has no spiritual significance, and it should be left to science.

As I wrote some time ago:
On the contrary, we have the statement of St. John Damascene, himself a Church Father, writing in An Exposition of Orthodox Faith, a summary of the Faith expounded by those who went before him:  

"Further, some hold that the earth is in the form of a sphere, others that it is in that of a cone. At all events it is much smaller than the heaven, and suspended almost like a point in its midst. And it will pass away and be changed." (Book II Ch 10)  http://www.newadvent.org/fathers/33042.htm

This is, in context, a completely clear statement from a Church Father that believing in a spherical earth is compatible with orthodox faith and no flat earther here has ever shown authoritative Catholic teaching otherwise.  

Just because St. Thomas and St. Bede fell for it, and that the Church was silent in condemning it for a long time, does not make it less of an error.

The Church has never condemned the idea of spherical earth.  You are perhaps confusing this with the condemnation of Galileo for heliocentrism.  If one reads this, one can see that spherical earth has nothing to do with the condemnation.  Catholics had been accepting the earth is a sphere for around a thousand years by that point.  Galileo was arguing against the accepted Ptolemaic model, one that included a spherical earth.  The other major theory around that time was the Tychaen model.  All the models under consideration included a spherical earth.  There is no evidence of anyone at that time thinking the earth was flat.

So it's "anti Catholic" to believe in a flat earth or flat plane? I also need to separate Catholicism from science?

It is factually untrue to claim that it is (or ever has been) a Church teaching that the earth is flat.  Historically, many of the people who have made this false claim have done so out of anti-Catholic motives.  I assume that the people making that claim on this forum are probably not anti-Catholic infiltrators but genuine Catholics who have been deceived.

There is no general principle that one must separate Catholicism from science.  Certain ideas in science must be modified or even discarded in order to conform to Church teaching.   On the particular issue of the shape of the earth, however, the Church teaches that Scripture is silent on the matter and it is therefore a question for science.

So it's "anti Catholic" to believe in a flat earth or flat plane? I also need to separate Catholicism from science?

It is not anti-Catholic to believe in a flat-Earth Mass 12. It is anti-Catholic to say that it was once Catholic belief that the Earth is flat.

As for 'faith and science,' well there is one you have to be very careful about. Science does not confirm a flat-Earth for if there was proof for a flat Earth then it could not be against the Catholic Faith. Truth does not contradict truth.

There is however, since 1514, an attempt to create a 'science' built upon ideas, assumptions and theories. This of course is the 'science' of origins, or what they call science but is not real science with established facts and proofs. Take the revelation of God's creation, how the world as it is was created by God. There is no science involved in such a creation.

But those who did/do not believe in God had/have to invent a 'science' that can be credited with the world as we find it. They made it up over the last 300 years, first that the world we see is heliocentric, then that this solar system evolved from atoms, that the Earth's crust evolved and formed over billions of years and that all life evolved and finally a Big Bang beginning that came from nothing. All this 'science' is not real science for it too is based on faith, faith that God doesn't exist so there had to be a natural case of origins. These they invented and called them science.

The greatest heresies, those that caused the most loss of souls, are to be found in these false 'sciences' of origins. Billions lost faith in God creating when offered natural secular 'scientific proofs' they made up. So Mass 12 you do not need to separate Catholicism from science, but you do have to know what is true science and made up science.

Those who believe in a globe earth will use all sorts of reasons as to why we cannot be allowed to believe in a flat earth; or, if they do allow us to believe it, they will place conditions on it. They have to control what we believe, even though the Church has not ever taught that the earth is a globe. They are generally very upset that any Catholic will not believe their view of the situation.

Of course those of us who love the Church are upset to see supposed Catholics affirming lies told by anti-Catholics.  We don't like lies and we don't like seeing the Church attacked.

I am not saying that you are not allowed to believe in a flat earth.  I am saying that you should not repeat proven false claims that the Church taught flat earth.  You have been shown overwhelming evidence that this is a lie.