Many people hit on Harry all the time. The cute barista at the cafe across the street, the librarian on duty on the weekends, the window cleaners of John Marcone's office building, John himself, Thomas, Sanya, Carlos, Molly, Susan, Karrin, Kincaid, everyone.

Harry isn't so much oblivious as he thinks he must be imagining things.

The barista who drew a heart on his coffee and gave it to him on the house then invited him back for more probably thought that he was a bum down on his luck. She was just being nice.

The librarian who waived his late fee, spent an hour discussing ancient Egyptian artifacts then invited him to the museum was probably just glad someone shared the same interests. Totally nothing there.

The window cleaners who smiled waved and offered to come over and wash his windows at a discount was just being nice and looking for business.

John was just sending him useful things to be contrary and mess with his head so Harry wasn't going to think too much about that.

Kincaid's lingering touches when patching him up was definitely due to Ivy's insistence that Kincaid help out. People didn't do lingering touches on Harry anyway

Things like that. Harry continually explains away all the more than friendly gestures cause he doesn't think it's probable that people want him at all.