Maybe it's the same reason why conservative actors can't get parts for films. Their online history gets scrutinized, and if you've said the "wrong" thing, or follow the "wrong" people you get blacklisted.
Maybe it's the same for tech?
Timestamped
lol.
The reason a lot of the self proclaimed cancelled "right wing" actors don't get jobs any more isn't because of the politics directly, it's usually because of the same reason a lot of actors end up dropping out of Hollywood - they may have been good at one time, certainly good enough to bring in the money so if they were difficult to work with it was worth dealing with them, but the moment you stop bringing in the money you start losing roles very quickly if you have a reputation for being difficult or have upset enough people that when you're no longer the top dog, the people you've potentially spent decades annoying and being hard for them to work with, they're not going to put a good word in for you, or chose you over another actor who maybe is a bit less experienced but isn't known to be difficult on set.
When you read the history of a lot of actors who basically disappeared for years you tend to find that the "being difficult" thing is often one of the most common reasons someone will go from being in everything (or so it seems) to being in bit parts. Meanwhile actors regardless of their political or religious leanings who get a reputation for being easy to work with on set are far more likely to last pretty much as long as they like, especially if they're smart enough to be willing to reduce say their pay demands after a flop or two, or do a few roles that are different to the one they got known for (thus showing they're able to do more than one sort of character).
Basically a key skill to long term careers in Hollywood (and many industries where your name gets known), is being known to be reasonable, and flexible.
IIRC Kevin Sorbo and Dean Cain for example were both actors who for a while were AA for TV work, Cain was Superman for years and Sorbo was Hercules, and then they both let it go to their heads, started becoming increasingly hard to work with and in Sorbo's case managed to tank a reasonably high budget TV show built around his character (so the producers couldn't even consider replacing him).with his demands/changes and never seemed to admit that maybe his actions had something to do with it, which made him increasingly unemployable as far as the big companies were concerned when he kept up the behaviour.
So I suppose they might have a "black list", if by "black list" you mean a reputation for for being hard to work with, and people remembering how their previous experiences went...