I think that many people "feel good" about rejecting others and some even do it to people that haven't expressed interest in them. I find the latter to be more offensive.
My strongest memories are from 3 different occasions.
On eHarmony, I paid $60 for a monthly membership and was matched to a man...he messaged me first. I didn't find his photo attractive, but I know that photos can be deceiving and we seemed to have a lot in common. I wanted to be open and thought that maybe we might click. Replied with a friendly message only to be proactively rejected with him saying he's only attracted to women that look like Emma Stone. I wasn't evening expressing interest...I was just responding to his initial greeting!
Another occasion...I was shopping at an electronics store and was looking to buy a music keyboard. The salesperson negotiated a lower rate for me but I wasn't looking to purchase that day. I asked for his business card and he probably thought he was doing me a favour and rejected me; stating he didn't want to give it to me and he has a girlfriend. Like wtf, I wasn't hitting on your rude ***, *******.
Most annoying of all...I was busy working at my cubicle desk and a colleague went inside and told me he was leaving for a new job. I congratulated him and he then said something along the lines that I should check out opportunities at the new company cause it's great. He then stammered and backpedaled a bit...clarified that he wasn't just saying it to me but to everyone. I felt he was concerned I would think he was interested in me. When he said that though, his smile seemed to widen. What an ***.
By some miracle, I'm not single anymore, but good god...if anything were to ever happen I wouldn't even bother dating or meeting people again. I hate people and wouldn't have the strength to go through it any longer. I empathize with you folks experiencing the pain of rejection and it's even more annoying when people go and proactively reject random uninterested people. I hope that you all find some luck quickly.