A lot of committed vegans I know don't sweat over it if mistakes are made on the "vegan" menu. They advise the staff politely, discarding what they can by hand and eating that they can't. Wasting a meal makes a mockery of the point of being a vegan in many ways.
This teenager possibly gets it. Dad is intentionally overdoing it. There is a lot we can learn about how to do better politics here. Perfection is the enemy of the good.
Edit: Obviously allergies and diseases are a whole other thing. There is a reason getting it right is still very important, but if that's the case nobody is messing around, especially not Dad.
Oh I certainly agree there are people for whom it's serious. That's not this meme.