"those who did not agree"

We must distinguish between those who explicitly don't agree, and those who say something wrong while thinking they agree with the Church.  Bishop John was speaking about the former.

Here's some common sense:

I have personally heard Society priests say wrong things from the pulpit, obviously without realizing it.

Sometimes it was a slip of the tongue. 

Other times it was clearly from a misunderstanding of Church doctrine.  I remember one priest saying he was corrected by a laywoman in the sacristy after Mass, and in his next sermon he publicly corrected himself.  Did he cease to be a Catholic for 1 day?  No.  It was material heresy, not formal heresy.  Archbishop Lefebvre used to say, "A young priest is allowed two heresies per sermon."  He was talking about material heresy stemming from misunderstanding.

Heresy only excludes a person from the Church when it is formal.

Once Father told us Satan was in Heaven, then quickly corrected himself.  Did he cease to be a Catholic for 5 1/2 seconds?  No.  It was material heresy, not formal heresy.

These Modernists say wrong things because they misunderstand Church doctrine, like the priest I mentioned who was corrected in the sacristy after Mass.  The things they say are so obviously wrong to you and I whom God has blessed with good teachers.  They are not so obviously wrong if you have been born and bred in existentialism, phenomenologism, etc.

A well-formed hierarchy could point out to the Modernist his material heresies and demand he give them up or become a formal heretic.

The drama today is that the highest authorities are themselves the material heretics.  I think it's St. Robert Bellarmine who said something about the college of bishops being able to confront a pope about his material heresies, but they're all Modernists also so don't hold your breath for that.

They say themselves that they are only representing what the Church teaches.  In charity I assume they are sincere, and gravely mistaken about Church teaching.

If they are lying and understand quite well they are teaching falsehoods, God will deal with them Himself.  May He have mercy on them, may He have mercy on judgemental sedevacantists, and may He have mercy on me.

I'm so glad we have evolved to know better now.  I'm so glad that I can pick and choose what is truly Magisterial in my profound sense of wisdom." 

Was St Paul being judgemental?
"But though we, or an angel from heaven, preach a gospel to you besides that which we have preached to you, let him be anathema.
Gal 1:8

What does anathema mean?

He sounds like a sede, doesn't he?  Was he being judgemental?

Can you please provide some Magisterial evidence for that?

His errors were larger and more abundant because his misunderstanding was deeper.  But just like the SSPX priest mentioned, Benedict thought he was in harmony with Church teaching.

While the SSPX priest was saying the words of Consecration, he had not yet recanted his error.  Was he anathema at that moment?

If no one pointed out his error and he held his misunderstanding until death, would he be anathema?