The real joke is that tracksuits are actually super comfortable and practical, and the punchline is that the people making fun of that wear uncomfortable clothing because of "fashion" or whatever.
The real joke is that you think it's a joke but it's just the way society works, expectations and norms do exist and if you can't live up to them, you will simply be dismissed.
Whether I agree with society or not is a different matter of its own.
