I need guidance on how to handle this?

Hello so there is a guy who I met in my class. He seemed nice and very friendly to everyone and he still is friendly to everyone but something happened that made me wonder what should I do. So the conversation of friendships and hanging out with people came up and he specifically told me that he is only just creating school friendships and nothing else, so I basically took that as he has no interest in hanging out with me as a friend so I left it alone. So now we just be polite, speak to each other, just a simple hi and bye. Well I was in class and there was a girl sitting right next to him and I heard her talking to him about the plans that they were making to go hang out and do things and he seem to have no problem agreeing to hang out with her, in fact he also had no problem with hanging out with any of the guys as well as he said that he had made plans to hang out with them. So I sat there and was thinking to myself why was I told something completely different than what he is actually doing. I accidentally walked in at that moment and heard them making plans. Well she seemed to be the one that was pushing the plans and he was agreeing to them. I even heard her tell him to not bail on the plans which I thought that was wild. Shortly after I sat down I see him glancing over at me and then the girl starts glancing in my direction too because she saw that he kept looking over there. Well I guess my question is since I now know this do you think it would be rude if I just ignore this guy and just move on and what I mean by ignoring... I mean do you think I should just stop saying hi or if he says hi should I just ignore this guy? I also noticed that when I used to hold just conversation with him in class he would talk and laugh but as soon as another female or someone else came around that appealed to him more then I was left looking like the outcast and just ignored while they carry on talking as though I don't exist much. Should I just ignore him if he says hi?

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Also I wanted to clarify that I never said that I was interested in this guy romantically and he knows that I am not interested in him romantically. I told him that I wasn't interested in dating anyone at the school or forming any kind of romantic interaction. He also agreed and told me that he wasn't either.
I need guidance on how to handle this?
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