"Clumsymum, just out of interest, how old is your DS, and do you have any other children?"
DS is 10, and no I don't have other children. I was, however a bit of a fussy eater myself as a child. Mainly because I spent a lot of time in hospital as a very young child, fed/weaned on VILE 1960's hospital food, and then a little bit spoilt by my Mum, who was trying to make up for all that.
However, I can remember going to other peoples houses for tea aged 8 or 9, and ALWAYS trying to eat what I was given, because I knew it was rude not to. Even if I only ate a small portion, then said "I'm sorry, I'm full up", it was better than making a fuss about what I was served. TBH I often found new things I liked that way anyway.
I do think children should be allowed to have likes or dislikes, and I have never forced DS to eat things he really doesn't like, as long as he gives them a proper try. He also has to be reasonable. If you like the tomato stuff on the bottom of a pizza, it's unreasonable to complain about 'real' tomato on the top.
I did used to get a annoyed about my step-kids (now grown up), who both refused to try any sort of cheese at all "Noooo, don't like cheese" but would munch down pizza or cheeseburger.
I tried to explain that all cheeses taste different, but they would have no truck with it at all.
Yes some kids like a wider range of tastes than others, but I do think some of that is taught, and those who don't like many things can at least be taught to be reasonable in their reactions to foods they don't fancy.