My only argument is that people download instagram because their friend /friends "liked" it on facebook. I can't recall anyone making a fuss about filters in the past.
I've always been a big fan of Instagram because of the filters. Most people that got into Instagram use it for that reason. It got popular on iPhone because of how it made your photos look. I don't know anyone who uses Instagram just because someone liked an image. I DO know quite a few people who STARTED using it for that reason though, but use it regularly for the filters. I am one of those people.