CathInfo.com

I don't have time to listen to each and every priest's opinion.  I go with what has been said in the past - Bishop Tissier and Fr Cekada both did lengthy studies and both agreed there was positive doubt.  When you get people from both sides of Tradition to agree on something, that's a pretty strong consensus.  And the matter of the new rite is not getting clearer, but only more doubtful as time passes.

It is curious how Bp. Tissier de Mallerais is still part of an organization that has an official position against his beliefs.

Do as I say, but don't do as I do.

There's no need to investigate a 'positive doubt'.  That's an oxymoron because a 'positive doubt' means it's already been investigated!  Only a 'negative doubt' needs to be investigated.

A 'negative doubt' is someone who has been arrested based on suspicion only and interrogated/investigated.
A 'positive doubt' is like a person who has been arrested and charged with a crime.  The cops already have evidence enough to charge them and setup a trial.
But the person can't be termed innocent/guilty (i.e. valid/invalid) until the Judge/Jury (i.e. Church) decides.
In the meantime, while we wait for the Church to decide, the only thing to do is to "conditionally" ordain/consecrate (i.e. post bail, wear an ankle bracelet, and go on probation).
In other words, the person is treated as "guilty" until the Church decides.  This is due to the evidence which supports is guilt.

Yeah, this might have applied pre-2000s, with valid bishops alive.  But now, no.

A conditional sacrament doesn't repeat anything.  That's why you're confused.
If tomorrow +Francis declared all new rite consecrations/ordinations invalid (let's assume he converted), then you wouldn't "conditionally" re-do anything.  You'd use the regular, non-conditional formula.

The conditional formulas exist PRECISELY for doubtful cases, wherein the Church has not decided and won't decide soon.  People can't wait around forever, thus, in Her wisdom, the Church created "conditional" formulas.
A conditional formula, based on a positive doubt (i.e. evidence showing problems) is not a sin.  That's why the conditional formula exists!!  For doubtful cases!


Why is this so difficult?

That is what I want to know, why is this so difficult?

Pax, it is a sacrilege to administer any of the three sacraments conditionally without first investigating each case individually. Trent's catechism on the sacrament of baptism.....

In Conditional Baptism The Sacrament Is Not Repeated

Nor let anyone suppose that it is repeated by the Church when she baptises anyone whose previous Baptism was
doubtful, making use of this formula: If thou art baptised, I baptise thee not again but if thou art not yet
baptised, I baptise thee in the name of the Father, and of the Son, and of the Holy Ghost. In such cases Baptism
is not to be considered as impiously repeated, but as holily, yet conditionally, administered.

In this connection, however, there are some matters, in which, to the very great injury of the Sacrament, abuses
are of almost daily occurrence, and which therefore demand the diligent attention of pastors. For there are not
wanting those who think that no sin is committed if they indiscriminately administer conditional Baptism...

...This certainly they cannot do without sacrilege and without incurring what theologians call an irregularity.
According to the authority of Pope Alexander the conditional form of Baptism is to be used only when after due inquiry doubts are entertained as to the validity of the previous Baptism. In no other case is it ever lawful to administer Baptism a second time, even conditionally.

You are posting as if you are one of those "who think no sin is committed if they indiscriminately administer conditional" Ordination.

Note the red text. The underlined teaches that initially, the Church presumes validity, and that there can be no conditional ordination until after due inquiry. That is the law according to the bolded red. It says so right there in Trent's catechism. 

So as you can see above, contrary to what you say there most certainly is the need "to investigate a 'positive doubt.'

There is no reason whatsoever for skipping due inquiry, none. If it takes 10 minutes or 10 hours to look into and investigate the matter for each individual, the Church requires it, it says so right there ^^. There is absolutely nothing complicated here.

You seem to think that because of what the NO is, that either this law abrogated itself at some point after +ABL, or was abrogated by the NO. The NO does not have the ability, nor possess the authority or power to abrogate this law, and neither do any of us - no matter how sure we think we are that all NO priests are invalid.