Am I A Stalker?
Since you asked, I would say Troll. Get over it and move on.
You're a loser and you have serious issues stop trying to force him into collecting cards, and you have no right to tell him he's no true fan if he doesn't if you said that to me I would beat the shit out of you.
Sounds like a stalker to me but here's my question; If you are a "Straight Male" than why are you chasing after some guy that clearly does NOT want to be friends with you? Maybe if you were nicer to him, respected his personal space, stop hogging all of the attention in the group chat you were in with him, stop making everything all about you, stop dragging him into your bullshit and making him feel uncomfortable all the time then maybe he WOULD be your friend.
But since you are such a toxic, attention seeking loser he got tired of your fucking bullshit and blocked you and you only have yourself to blame.
Like seriously he was just trying to check out at Walmart before you followed him to the checkout line and he gets angry at you. Did it ever occur to you why he's angry with you? It's because he doesn't want ANYTHING to do with you, and also you don't follow someone you think you know at the checkout counter at Walmart that right there is an instant red flag and i'm a bit surprised he didn't call Walmart security to have your annoying ass hauled out of the store because that right there is considered STALKING.
You really need serious help, here's an idea why don't you go chasing after women if you say you're straight instead of chasing after guys who are really uncomfortable with you and don't want to be your friend. That is if you don't end up turning away women and get any sexual harassment allegations on you and it wouldn't surprise me at all.