How exactly does setting the block size limit constitute as a vote for that block size? How would anyone else know that you set your node to accept a certain maximum block size? If there is no mechanism for this (and I couldn't find any in the code), then a lot of things said here are wrong.

If there is no mechanism that tells everyone else what they are accepting as the max block size, then there is no voting happening. A sybil attack wouldn't work since there is no voting.

Additionally, miners wouldn't know when to increase the block size as the safe method of deploying the block size limit as a hard fork is no longer there. It could result in either nothing happening as miners want to play it safe, or the blockchain forking in multiple ways as miners test out different block sizes. Either way could be catastrophic.

Lastly, why would it be a good idea for users (especially non-technical users) to decide what their block size limit is? Not everyone is smart enough to know all of the implications of why a certain block size limit should be accepted or not.