If their terms of service say “thou shalt not reverse-engineer”, and I want to connect my Facebook to my Friendica, UK law says that I'm allowed to do so, and Facebook is not allowed to have a problem with it – any clause in a contract that says otherwise is to simply be deleted.¹
¹: Technically, I think “ignored” is more accurate; if you're prohibited from reverse-engineering in general, the general prohibition would still apply even though it has a specific exemption. I'm not a lawyer, though.
Similar situation here. I also have certain rights that Facebook tries to deny me through their contract clauses. I consulted a lawyer and was told those could be ignored.
Apparently it's a thing in the US. People can sign their rights away to these companies. Needless to say, those counter-rights clauses have become standard in every contract. Read one of these abusive contracts and you've read them all. "We reserve all possible rights while you promise not use any of yours" summarizes every terms of service out there.
¹: Technically, I think “ignored” is more accurate; if you're prohibited from reverse-engineering in general, the general prohibition would still apply even though it has a specific exemption. I'm not a lawyer, though.