Philanthropy gone awry

Last night... A simple evening trip to the grocery store (yes, I shop at 10pm - it's quiet and I'm a night person, deal with it)... turned into something odd and thought provoking...
So, I pull up to Hannaford's at around 9:30pm (Sunday night) and I notice a homeless man sitting on the bench right outside the entrance. Well, I should say that my first impression was that he was homeless - it's 90 degrees and he has heavy clothes on, he's very scruffy and thin, has a beat up suitcase in a shopping cart and he has bags upon bags of newspapers, coupons, etc. and he seems to be making himself right at home on this bench - first thought... homeless, right? So... I go inside spend about an hour or so shopping. On a related side note, I was craving chocolate ice cream the whole way to the store (which may or may not have prompted my grocery trip.. don't judge me!) So at the end of my trip, while in the frozen section I grabbed 2 individual sized Ben and Jerry's Chocolate Brownie Ice Creams - they were the individual sized ones... not the pints, really! One for tonight, and one for later on in the week when the craving visits again. I went outside to my car, grabbed the ice cream and started to eat it... right in front of the bench guy. When I thought, wow... I'm so fortuntate to be eating this fantastic (and it was!) ice cream on such a warm night... I should share my second one with this man. I was about to drive off , when I reached into the bag instead, got out of my car and approached him with it. The following short dialogue ensued...

(Me) "Hey, do you like ice cream?"
(Bench Guy) "Excuse me?"
(Me) "I have an extra ice cream, do you want it?"
(Bench Guy) - with a frown and an eww face - "Um, sorry, I don't eat dairy or meat"
(Me) - nervous laugh - "Oh, OK... I'm sorry" - nervous laugh... can't get back to my car fast enough.

I shut the door to my car, drove a block and and felt awful... At first I thought it was because it had all gone down so opposite of what I had expected... I originally had the vision of my thoughful gesture being reciprocated with a kind smile or a thank you, or a "wow... people are really good after all". But instead a scowl and a smug response. I thought about this all night... and then I shared the story with Korey and he actually had some valuable insight. I felt bad, not because I had clearly not offered up a vegan option he could enjoy, but because I judged him and I was wrong. He had a story and I just wrote it for him instead of hearing it. I really thought I was nicer than this, but no... I'm a jerk.