what's wrong in being what is called "Old Fashion"

I really can't understand the meaning of "Old Fashion", people often use this when they discover a part of someone's personality or habbits not welcoming few aspects of current modern life.

The issue is that when someone is labeled as Old Fashion, it is as if this person is accused of committing a crime! What's wrong in not being interested in some of the modern fashion styles?

Is it really an accusation to be old fashion?