For the traditional law and order crowd (not so sure now) wearing anything the US flag is unlawful until 1989 but now is still considered poor Etiquette and rarely acknowledged as such.
Also, the flag code is merely suggested standards for how to care for the Flag, and not a law that citizens must abide by. To go further, there is distinction between the flag, and flag motifs. Flag print toilet paper, totally okay, flag print jockstrap, totally okay. Taking your purpose made American flag, and wearing it as a cape, not okay. Wearing an American flag print towel as a cape, totally okay.
It has other uses. Excessive use by others can identify them as people you should avoid, while flag burning is very much in the spirit of that toilet paper.
Yeah It's pretty ridiculous. There's been lots of cases of people who attended a flag burning for the fuck of it and ended up on a watch list. Even the guys who do it annually just as a statement that they can ended up on there. It's not technically illegal but the state REALLY wishes it was.
A flag is a piece of fabric. People who swear their allegiance to it only tell the people more powerful than them that they will do any horrific things they are told as long as it uses that exact pattern of colours. They lose their individualism.
Ahh, so the goal of this meme is to reemphasize the right to free speech and expression and to remind people not to lose their individuality by being nationalist. Fair enough.