We're not talking about forcing anyone to do anything. We're talking about the default relay policy for Bitcoin Core. If it were a matter of forcing anyone to do anything, why would a 40-byte OP_RETURN OK and not an 80-byte OP_RETURN (again, the original, publicly-announced, merged-into-the-codebase plan)?
40-byte OP_RETURN is potentially unavoidable for some things (no, I don't know any examples).
The answer is stealth addresses, which fit nicely in 40 bytes, are completely random by design (so are incompatible with semantic filtering) and add significant value to the network. I'd like to know why you are so engaged in this conversation, when you don't know about probably the most talked about use-case for the feature under discussion? In fact, why are you trying so hard to influence default relay policy, which has no direct effect on 'blockchain spam', when your aims would be better served by convincing other miners that you're right?