I really don't understand what any of this has to do with "trust", especially of the project or code. If anything people who want to gain undeserved trust would be incentivized to appear to follow a higher standard of norms publically. The public comments would be nice and polite and gregarious and professional, and the behaviour that didn't meet that standard would be private.

FWIW I've never programmed a line of code in zig and I don't know who this developer is.

All I got from it was "seems like GitHub is starting to deteriorate pretty hard and this guy's fed up and moving his project and leaving some snark behind".