Spam as a verb means: "Sending the same message indiscriminately to (large numbers of recipients) on the Internet." Perhaps they are under the impression that you're doing this. A simple way to avoid mistakenly sending people spam is to tailor your comments to be more personalized to either the author or the content of their post. I hope this helps!
RE: The Okey-Doke - Derek Chauvin Charged with Murder