... I mean, sure, Harry could have been in Thomas thrall, but then, I think he would not be able to do normal wizard things ...
I think if the whampire just crushes the wizard's will with overwhelming lust, said wizard likely couldn't muster the focus to flickum his bickus, iykwim.
But a more careful, slower seduction... or giving them some recovery time (while still keeping them on a psychic leash)... wizards treated that way could (I think) still be very capable.
I don't recall which story it was, where Harry discovered just such whampire controls buried in a lawyer's mind, leaving the very-finely-disciplined legal intellect essentially unimpaired. I presume it would be similar for a wizard, and
their mental discipline.
... And if they really think that Thomas "captured" Harry, then they should have do a research to try to save him, or, at the very least, completely cut their ties with him so Harry cannot tell the whampires any Council secret. That is precisely my point, everybody seems to be disgusted that Harry is with Thomas, but it is half-assed. Like, they should take one of these two positions a) panic that Harry in on a whampire pocket. Try to save him or consider him lost b) shrug and decide that Harry is not in danger and he can choose who to date/have sex/whatever. But they seem to be in a middle ground, which I do not understand well.
I find this very well-reasoned & persuasive. I can only "make excuses" for the White Council here; explain how their motivation
could work out to the actions they did. They clearly didn't do things they "should" do (as you clearly laid out, above).
To begin with, I think the WC is stultifying under centuries of tradition and multiple layers of no-longer-relevant bureaucratic policy. In particular, much of the supernatural world is roiling and unstable
and innovating, in light of the upcoming Starborn Cycle terminus; but the WC hasn't adjusted or adapted. In particular, they have a tradition of letting every wizard do whatever, independently, and only step in with Warden Action when the wizard goes too far. So they may be a bit suspicious of Harry being whampire-dominated, but
that's his business until/unless it goes towards breaking the Laws of Magic.
That scene in Peace Talks where Ramirez & Co confront Harry about Lara, that's the WC beginning to "take official notice."
There's also, I think, some "we are the White Council" arrogant blindness going on, related to the aforementioned uptick in supernatural action (which the WC hasn't matched, or adapted to). They don't/can't believe any group would be so self-confident as to attempt such a brazen subversion of a WC wizard and warden.
The WC hasn't noticed -- as an organization -- that many of the other supernatural powers have in fact become
much more-active and
much more-aggressive, and that they -- the WC -- are beginning to look (to those predators) much like an aging buck: still impressive, but no longer
quite up to the task of protecting the herd... or itself.