Federation is a sub-category of decentralization, so if they reject the latter it's usually obvious they don't plan to support the former either.

Besides, their reasons for not running a decentralized service do apply for a federated service as well, and as far as I can see, they're using the terms synonymously anyway.

Whether those are good enough arguments, that's another debate.

>At the end, none of those three questions are answered for me.

Well, it's still their answer, and that's what my post was about.