New user cannot disable "mailing list mode"

I’m new user. I just signed up to contribute to a post with a potentially useful answer.

Meanwhile, my personal email inbox was bombarded with some undesired email notifications of new users’ posts from this forum. Moreover, I cannot disable those email notifications or untick “Enable mailing list mode” in Preferences > Emails, because I got a warning saying it’s read-only mode. That is until I somehow earned a badge for reading guidelines.
Anyway, please make default to disable the mailing list mode. I was quite mad of that.

The site was in read-only mode for everyone. I haven’t yet found a setting to alter the behavior, if I’m unable to I’ll raise an inquiry with Discourse to see.