You are tripping. Old accounts mean alts, new accounts mean bots, frequent posts mean shills, infrequent posts mean alts again? No need to actually critically engage with any disagreement when every permutation of account activity can be unfalsifiably depicted as illegitimate!

I never worry about someone being a bot or a shill or an alt, because if they’re making a bad argument, I can just present my reasoning against that argument, and it doesn’t matter where it came from. Your points look a lot stronger without trying to question your opponent that way. After all, if a bot posts that the sky is blue, I don’t think you’d start thinking the sky is green? So face a bad argument with a good argument, rather than a fallacy. Do your stance justice.