You might be surprised to learn you can be booted off a flight for your attire, hygiene or odor.
To be fair this dudes t-shirt had Trump giving the middle finger. They try to turn this into political gasoline but in reality it could of been any person on the shirt. The problem is the offensive gesturing.
Is that the bar for what should be disallowed on planes? By your logic I should be able to bring an airhorn and spray fart spray down the aisles.