A lot of people dislike it for the privacy nightmare that it is and feel the threat of an EEE attack. This will also probably not be the last time that a big corporation will insert itself in the Fediverse.
However, people also say that it will help get ActivityPub and the Fediverse go more mainstream and say that corporations don't have that much influence on the Fediverse since people are in control of their own servers.
What a lot of posts have in common is that they want some kind of action to be taken, whether it'd be mass defederating from Threads, or accept them in some way that does not harm the Fediverse as much.
It's worse off if we don't federate with them. That way they get their walled garden and people don't bother to use mastodon as it's incompatible. Federation gives everyone choices.
Large numbers is not the same as quality content. I submit as my evidence ... well ... Facebook. And Twitter. And pretty much every corporate "the numbers go up!"-based social media site.