for profit corporation being able to suck up your posts is probably what has many upset
They can already do that without a bridge. And it doesn't "suck up your posts". It works just like any other instance. They have to search for you and follow you. Then they receive posts going forward, but they won't get historical posts.
I personally would block such a service
Good! You can do that and that is a perfectly reasonable solution. That's part of what has ppl upset on the other side of this argument. All of this arguing and vitriol is happening over a service that you can block like any other fediverse actor.