Yep people are strange arn't they. As you say some meet up groups are very cliquey and if they perceive you are not going to be 'one of them' they freeze you out. That's what I think happened, eg the photo and the age difference. It's the herd instinct. Remember back at school. Same thing. Could be also that you were a bit
over sensitive. As divine said ' drive safely' is just a throwaway farewell line.
I would give it another chance. Make a point of talking to the people who you thought were friendly and tell them how you felt last time but admit some of it could be down to you.
I hate being in photos too. I am a very short man and not very photogenic and am always the shortest in a group by quite a bit. I had to leave one meetup group through being ridiculed because of my height. It does make you wonder if trying to get out and socialise is worth the effort. But what's the alternative.