Burger King BK Other customer vomits on my food, staff told me to deal with it because the customer is old! Internet, New York

I went to BK with my son, and we both got a tray, and sat down to feast.  Well, some old, deranged, and somewhat disoriented man comes in, and sits down on the same bench as my son and I.  He didn't get any food, he just sat there, staring into space.  I had my son and I get up, and move to another table at a different part of the store.  I don't know this guy's deal, but I guess since there weren't very many people there, he wanted to be by us?  He moves and comes sit down again on the same bench that we are on, and he is sitting next to my son, staring into space, and even started to drool.  I got up and switched seats with my son, so I was the one sitting by this mental guy, rather than my son.  At this point I realized this was ridiculous, and was close to just getting up and leaving right away.  Sure enough, just as I expected, within a few minutes, the old man, drooling and staring into space, vomits ALL over my tray of food and the table.  Thank god nothing got on me, and thank GOD I had switched seats with my son!

I got up immediately with my kid, walked up to the counter, and showed them what happened, and I asked for a refund or a free meal or something.  Their response?  "Oh, that's just ole Arthur, he's always been coming in here for years, he doesn't mean any harm, he's just old".  I said I don't care if he means harm or not, but my meal is ruined and I want some compensation, and then the manager came out and said there was nothing they could do, that they do not refund customers based on the actions of other customers.  I told them this was atrocious and I would be calling their customer service number, and the manager said "Good luck with that".

I'm not actually going to call some number and sit on hold for hours over a $10 meal, but I definitly will never go to that store again, and am APPALLED that this is simply shrugged off by the management!