I'm sure we all know people like this but it isn't enough for them to be happy about their own situation or stuff but they have to belittle others into the bargain just to shore up their own position. Its also in the way some people react if you do something out of the mainstream or just not what they would do, they snickering and sneering. I suppose its a form of social pressure to conform that was expected in school days but I'm surprised to see this still in evidence in adults!
People like or do things all the time I have no interest in or don't value for myself but I accept that people like and value different things to me and I respect that. I also see no need to try and make someone else feel small or lesser in order to boost my ego or status. Perhaps I am wrong but if you actually felt so confident in yourself you wouldn't need to do any of that so I suspect these kinds of behaviour are betraying insecurity, is that unreasonable?