You're entitled to an opinion about it, but a Slack bot that pings you when you say "guys" is not remotely comparable to bullying (which is the top-level claim in this thread).
I would consider it a form of harassment and such petty language policies would certainly impact my desire to participate in a community. I would feel unwelcome.
> I have never seen or heard someone chastised for using “guys” informally
A bot that is doing this is tantamount to a person doing it, since a person made the bot and a person installed the bot.