Card altering directly threatens PSA’s business model and they have already been forced to pay out for altered cards they graded which subsequently disintegrated in the slabs. If anything, they will be addressing the issue because it is a financial liability for them and not because of some moral opposition to altering cards––although I’m sure that’s a reason too. TAG is not uniquely positioned to detect altering, in fact it’s the opposite. Many alterers specifically send cards to TAG and other less-experienced grading companies because they have a higher chance of passing the cards through.
PSA’s “cleaning” service was just wiping the cards down to remove dust and fingerprints, but it was overblown online as many things are.