Are guys like detectives now

I don't understand but like this random guy from church somehow found my Instagram like I went to church yesterday against my will and we were also having like this thing we all made food and we would all eat it and I was helping the girls clean and serve on the men and then this guy asked me for a water so whatever I gave him something to drink and he says thank you and that's literally the only interaction we had he somehow found my Instagram in night and I don't even follow anybody at church so he couldn't ask any of the girls for my Instagram like how did he find my Instagram it's not even my name on there