Yeah, some kids need persuasion in order to eat a more varied diet, so that's probably where the thinking comes from, but like anything if taken to extremes it becomes abusive.
Now I'm middle aged and have developed a bunch of food allergies, so I've been forced into picky eating :-(
I'm 48 now, used to be like you. Now I have to do exercises to sort the bits that manual work and sports don't reach ... if I don't exercise properly I can't do the manual labour without a lot of pain :-/
It's not so bad once you get used to it, just put on some pumping music and enjoy the endorphins :-)