Well, right now Meta is pushing, not pulling. Meaning, Threads content can be displayed on Masto, but not the other way around.
IMHO, the bigger threat is having Threads content completely dominate other activity pub clients. Other clients / communities could get dependent on it. Then Meta is basically a drug dealer with leverage.
Data collection doesn’t bother me too much. I’m not going to install their client and all of the behavior trackers that come with it, and my activity pub content is already freely available to query on the internet. If they want it, they already have access to it. Everyone does.