If there was even the slightest ambiguity here then sure, you'd have a case. But since it's your unequivocal position that the Armenian genocide did not take place, and given that you yourself have made this front and center of your persona here on this forum, the post in question was disruptive and OT, but not exactly libelous.
I presume, wrongly perhaps, given your opinion on the issue, that you do not think that being an Armenian genocide denier is a bad thing.But feel free to correct me here. If you believe an Armenian genocide denier to be a bad thing, I'm willing to make a 180° turn here.
This is entirely different with Abdülmecid. He would be in the right to smack Ponti down hard without even making any statement at all regarding the "issue". Just because he's a Turk, doesn't mean he's a denier, nor does Ponti have any right to force anyone to make a statement on the issue, same as no one can call Ponti a native American genocide denier unless he specifically and unequivocally presented himself as one.
E.g. I do not have any issue with someone calling me a White genocide denier, since I do explicitly deny
this crazy fringe theory to be true at all.