No, the father and the son are idiots and in the wrong. They clearly and intentionally incited an incident and then had a hissy fit when they inevitably got called on it. I hate people who do this sort of garbage.
It is like the 8 year old who learns what you call a female dog and tries to justify to his parents why he can now say a word he knows he isn't allowed to.
BTW, the statement the father made is "I am a huge attention seeking idiot"
Perhaps to a point true. But often we jump to conclusions too fast. As a couple more examples, I've seen a shirt that says "I play dirty" on the front. ( Imagine the looks from parents at a TB tournament ) But on the back is some guy ripping though the mud on his 4 wheeler. I saw a kid wearing a shirt that says "I shoot first, ask questions later"............on the back is a person shooting a basketball from the 3 point line. Are they inappropriate, or only because we have passed judgement without knowing all the facts ( rear of the shirts )?