In most cases, you can send to a mailing list without subscribing, and people will include your email when they respond. I've filed multiple bugs this way. It was as easy as sending an email and attaching a patch.
Anti-spam measures are a large part of what made using MLs so annoying. From a moderation side, MLs are more work for that reason as well - Github and Gitlab at least get rid of spambots shilling shady cryptocurrencies, weenie enlargeners or questionable quality designer drugs. With MLs, all of this ends up in your moderation queue as well.
All the relevant mailing lists for my interest projects have web interface/archive, I can selectively reply/participate in any or no ongoing threads, and stop at any time.