Community rules. If 4 communities were in the same thread at once this would be harder for moderators to moderate, and for users to follow the rules/report. Since they can't tell easily from which thread this comment comes from
Threads are not always crossposted with the same context. Example:
I respect how up-front it was at least. I mean, i would've prefer at the very least to make it source available to see if it's trustable, but it's his choice, i guess.
The option was also called "not open source / have trust issues" but i mean, no hate against the dev but i see no reason to trust it off the bat. Yeah, the response was kind of immature.
I get open source can be stressful. for example, the summit dev not making it open since they don't want to deal with PRs/issues but at the very least make it source-available. From my POV this is a cool extension that popped out of nowhere, it's risky to trust that.
Not to be rude, but if you acknowledged you posted it in the wrong community, why did you keep it up?