As for the value of pilot selection and aptitude tests, nobody on Pprune questions the merit of GAPAN or RAF tests, but then they turn and say those with a for profit business model are manipulating doe eyed wannabees with selection testing.
Quite a few airlines use similar tests, both for selecting fATPL and ATPL holders, as well as for choosing their cadets (granted, there aren't many running cadet programmes lately).
So what we have is a case where some organizations are seen as credible and some are not and therefore, their tests must be "hogwash."
There may be rubbish tests and rubbish testers out there, but every company that hires people uses some sort of filtering technique and so does every university and every Integrated fATPL course. All of them will result in both false negatives and false positives, but a for profit company couldn't stay in business very long if they had too many of either.
All of the major FTOs use selection tests and the large number of people they assist into the career with a large number of airlines speaks perhaps as loud as those with an axe to grind against school XYZ (insert the FTO you dislike in place of XYZ).
If FTOs really are greedy morons as accused, they would just bin the tests and take all comers. If wannabees are such dimwits that they need to be made to feel they are elite in order to get them to train as a pilot...well, that's the best argument I've heard yet for why there ought to be some selection tests.
Perhaps the truth lies somewhere between the extremes. Just sayin'
The O.P. seems intelligent and thoughtful enough to make up his own mind whether he had a bad day, a false negative, or maybe he does need a bit of work on his team techniques.