There are nearly 100,000 ASNs. Some are very small. An ASN is enough to identify a user's ISP - enough for someone significantly more malicious than you to, say, social engineer an ISP, report players to their ISP for "hacking" a site, or start correlating with their visitors.

What we're also missing is the context. Did you share the ASNs for the purposes of, say, debugging a network connection? For statistical purposes? Or was the message more "look at the people connecting to my server, j/k these are just ASNs"? The tone you use matters too: by sharing ASNs, you could easily be hinting that you have people's real IPs, and that could be taken the wrong way.

I don't doubt that Discord overreacted here, but I certainly think there's a high chance that your message could have been misinterpreted as a threat to privacy.