I'm going to cut contact with my friend after getting turned down when I brought up a relationship
Was there a reason you told them about the relationship?
Yes, I was feeling vulnerable then.
That is your friend though. You should try not to cut them off over silly reasons. You should respect differing opinions.
Well my friend is a loser since they can't handle the relationship.
It is wrong to cut people off from your life if you are friends. You should respect peoples wishes if they say no, no means no.