I mean, it would have been a similar process anyway with any other game engine…and Steam requires a monetary investment to post a game anyway, I’m pretty sure, which does help prevent a lot of crap building up. (I’m not sure how it works for free games though…anyways I never aspired to become a big game developer…I just enjoy tinkering and fooling around in MakeCode Arcade!)
You can also use Tauri to get it down to ~10 MB, or 2.5 MB if you compress with upx, although I’ve heard antivirus software doesn’t like compressed executables. Regardless if you were distributing a game on Steam, you probably have the money to do code signing anyway. Additionally, the typical binary.js in a MakeCode Arcade game is several MBs, not only a couple of hundred KBs as I estimate, although I could just be busy looking at larger games, which are most likely the ones that would get packed up for an executable anyways. 
No comments is easy, but no private conversations is a harder one to satisfy for such a site, as if there is going to be user-generated content, there must be a report button and therefore flagging and reporting must be implemented, which naturally leads itself to private conversations between the person who flagged it, the offending person, moderators, etc.. Or, GitHub Issues is used once again but I would give more people to edit the repo / database and let them close issues so it’s a team basically.
Maybe just some more work would be needed to put into the descriptions, examples, etc. Additionally they would link back to the forum posts where these extensions originated, as all conversations around MakeCode Arcade should be happening on this platform anyways 