I think it's just as simple as "if you want to interact with people through software you have to use the same software as them." Nothing controversial about it, its just that the interaction isn't chatting over telegram, it's transacting.

There's nothing stopping you from selling your ether to someone who wants it and deploying that capital on something else. Or ignoring it and forking the chain and keeping your fork ether. "But it's valueless" I hear you say, see my above paragraph for the answer to that one.