We're Not a Match

I have not heard those words very often, yet I can't seem to get past a first meeting with most men I've met online.
One first meeting was very promising I thought -- pleasant, easy chat during a walk.  We even had a snack later.  When I asked my date if he usually knows right away that it's a match or not he was quick to assure me that he takes his time.  I relaxed thinking that we'd have a second get together to continue to explore the possibilities.
Three days later, the email from him said he didn't think we are a match.  He admitted to it being a difficult decision and even offered to talk, but I didn't take the bait.  What would be the purpose if he'd already made up his mind.
He is the exception.
The most humorous 'unstatement' came after I met a man at a restaurant near public transit.  I was keeping an open mind about having a second meeting; the gentleman wasn't making my heart go pitty-pat but he was pleasant and I was willing.  We walked together to the transit hub where we were heading in opposite directions.  He suddenly said he had to get home and put his father to bed (it was 6:30 p.m.) and took off like a sprinter to catch his departing vehicle.  Wow.  I didn't see that coming.  The next day he said if I wanted to be just friends and hang out that'd be fine.

Maybe I'm just not savvy at reading the signs.  How many ways are there to say We're not a match without actually saying it?  What is your experience.