So if an ignorant/malicious user creates a room without E2EE and doesn't care to enable it even when requested, all users are forced to converse in effectively

So if an ignorant/malicious user creates a room without E2EE and doesn't care to enable it even when requested, all users are forced to converse in effectively plaintext, and the solution is "clients tell users it's not E2EE". IMO it should be the case that it's always E2EE, no other options. Until that's the case I think Matrix ecosystem isn't keeping up with centralized solutions like Signal.