a bunch of my friends made accounts around the same time for a specific game
Which might have contributed to whatever the spam filter looks for. The server has access to all sorts of information. A bunch of newly made accounts, possibly even with similar mail providers and connecting from the same region to post on the same game? That fits the bill for what was happening before the spam filter was made extra aggressive: the same game would get spam comments several times a day, each day. I saw it happening on some games. You could go there any time of the day and there were fresh spam comments.
Gating comments behind some spam filter negatively affects games' popularity and thus potential profits
I do not think so.
Comments are still being made. Lots of them.
What did negatively affect games were all the spam comments. Some developers even disabled comments entirely because of that.
Some example theads
https://itch.io/t/5320326/spam-attacks
now it has increased to multiple per day
https://itch.io/t/5401726/spamming-with-adult-games-link
I can't keep up with blocking and reporting all of them, because new accounts just keep popping up nonstop.
https://itch.io/t/5495538/no-links-in-comments-moderation-do-something-about-thi...
I constantly have to block such accounts and delete their posts, but where is the administration?