This is my experience and perspective on parents forcing their children to eat. Growing up, my mother never forced me to eat anything. She would insist I try something, but sometimes I didn't, and I was not punished for refusing. She would fix me food I liked. And although I am picky, I liked foods from every food group. I loved tuna salad, green beans, plums, just about any meat besides fish, and much more since I can remember (as young as 3). There were some things I didn't like though, mainly because of texture. I loved hamburgers, but not ground up meat like you'd find in lasagna or chili. So my mom, though she loved those, stopped making them unless enough other people were going to be over that they could finish it, and then I'd get something else like a sandwich.
Contrasting to that is my dad's house. At my father's, you ate whatever you were given (or not given on some days where I had to scrounge around until giving up and making a mayo sandwich before bed). If chili was made, you were expected to eat it. And you sat at the table until it was gone. I remember to this day sitting at the kitchen table, crying until midnight and everyone else was asleep before getting up and going to bed hungry because I didn't want what was on my plate because I just didn't like it. There were days I went without eating. I didn't just want burgers and cookies. I liked lots of foods. But it didn't matter. I was 'spoiled'. Spoiled. Spoiled means damaged to the point of being no good. Hearing that as a child is damaging in itself. Especially when you can't help your taste buds.
In my experience, force feeding did not make me less picky.
My husband has a different perspective. When he was growing up, his brother just didn't want to eat. He went without a bowel movement for 2 weeks not because of constipation, but because he just wasn't eating. He wanted to play. That was it. So his dad sat with him at the kitchen table and would swat him with a fly swatter anytime he attempted to get up until the food was gone. That included food he did like, and food he didn't like. He continued to be picky despite his father's tactics. He did stop being picky as an adult, around age 26, when he decided for himself that nutrition was more important than flavor or texture, and now he's one of the most adventurous eaters I know.
But force feeding did not make him less picky.
The other type of experience some parents deal with are children who throw fits, back talk, and manipulate, trying to get fried foods or dessert rather than the main meal. This is a little different. If the child is hungry enough for dessert but didn't eat their main meal, they shouldn't get sweets just because they want them. If they're hungry and food you know they like is on the table but they want dessert instead, I understand not giving in.
I have also seen parents insist their kids try everything on their plate, even if it's the tiniest of bites, before saying they don't want it. I understand this too. But the kid not being able to leave the table until they eat it? Or making them try something they've had before and you know they don't like? I don't think it's fair. I plan on asking my child to try everything on his plate, but if he doesn't like it, he doesn't have to eat it.
Because in 5 years, 10 years, whatever, they will remember going to bed hungry or being forced to eat something they hated. But will you remember if they skipped a serving of fruit one evening out of their lives? I doubt it.
Disclaimer: I cannot judge for every parent