That's not "less". That's way more.

Google prioritizing their offerings over other vendors on a search they control is far different than "Can't post on Facebook from Twitter".

Google has put itself forward as a fairly agnostic search. No one signs up to be indexed by Google. It works more like a common good. So when Google starts offering a service, then puts its own offerings before others in its search. That's dirty pool.

But that's not what's happening here. Facebook is a platform to connect with other people who are also on Facebook. It doesn't purport to be a central hub for anything but Facebook. It's just not allowing Twitter (and others) to post on users' behalf.