To an extent, but morality is important to me too.
I don't use Facebook because they corrupt democracy. I don't use Twitter because Elon Musk is a wannabe fascist. I don't use Reddit because they have refused to clamp down on bad actors and have directly insulted their users.
If everyone defederates from Threads, I won't use Threads, because I don't use Facebook. My morals are more important to me than audience size.
But... as things stand, once Threads federates with the wider world, I will be able to interact with my friends without letting Zuck near me. In a most ideal world, they'd be able to follow me here on Kbin and I can follow them back. I'd see their posts in the Microblog feed and sorted into magazines, and I can like and comment and boost without logging into Zuck's website and letting him have my data again.
You can say that's supporting Facebook. Maybe. But if Threads is truly federated, then Facebook would basically be able to go anywhere regardless; in that sense I'd be supporting Threads whether I was talking to someone directly or not.
And in that sense, I totally see why people say "we shouldn't federate with Meta, they're evil and they're selfish and they're going to destroy the fediverse." I can understand why people personally would want to choose somewhere that doesn't do that. I don't think this instance should block Meta because it's large and general-purpose, but somewhere like Beehaw where that sort of thing is part of the mission statement... I get it.
But from my perspective, I am given the chance to talk to a large group of people; people who share the same interests as me; people I know in real life. People who would see my stuff - but (more importantly) I'd also see theirs. And I'm sure most people feel the same way; they're going to where the people are. This'll naturally create an audience, one that gives a wide variety of fresh content and also responds to content you give.
I'd much rather have that then return to 2020-era Mastodon where you'd be lucky to get 3 interactions to a Toot, and you'd see everything there is to see in 15 minutes (at most).