Um, wow, that is REALLY not right. For the trained therapists to do that... is pretty much called "forced feeding" and can be seen as cruel.
I think it is totally wrong and not appropriate.
It is actually horrifying... what they are doing... it is purely wrong and cruel. And you... should not get sucked up into it or let them decide for you...
I would just stop them.
A child this age, does not HAVE TO EAT VEGETABLES... it is not a "law." Ease up. When he gets older, he will naturally get more adventurous. I know, some ADULTS who don't like vegetables... do we as a society FORCE an adult to eat vegetables? No. So, why do we do that with a mere child? Their taste buds are still developing as well.
Next: when I was in grade school, there was a Teacher there who FORCED the kids to eat EVERYTHING (and the vegetables) on their plate no matter what. She would look over all the kids shoulders and yell at them and tell them they could not leave until their plate was completely ALL gone. Many kids, cried over it, or stuffed their napkins with food to pretend they ate it. Is THIS what you want your son to experience????
Next on with my story: anyway, so the Teacher did that to me a few times. I cried. I went home and told my Dad. He nodded. He was upset. He called this Teacher and invited her over for dinner at our home. She came over. My Mom made a great dinner. It was pleasant. Then, looking at the Teacher's plate, my Dad said to her "Hmmm, you didn't eat everything or the vegetables on your plate. You CANNOT leave our house or the table until you eat EVERYTHING." Then he stared her down. She was aghast and upset. My Dad then told her "Well, isn't that your rule? In school that is what you do to the children... force feeding them to eat... so I expect YOU to do the same and follow your own rules..." My Dad told her off. I was PROUD of him.
Next, it turned out that MANY parents complained about this cruel Teacher... but, my Dad was the most direct one... this teacher was reprimanded... and I think was fired. She was actually abusive. Cruelty is that way.... even if disguised as "discipline".
Your son's school... is harming him... and THEY will give him more food hang-ups and will teach him the wrong message about food. Food should be about knowing when you are "full" or "hungry" and listening to your body's cues.... NOT "having to eat" because of "rules" or for pleasing people... THIS is how food dysfunctions are developed. ie: bulimia etc.
Your son is NORMAL... many many many many many many kids do this... it is food phases. It will come and go. Do not make it a battle or give him hang-ups about it.... as I said, MANY adults do not even eat vegetables nor what their wife or Husband wants them to eat either. So why the double-standard about it with kids? Eating is a very personal thing... it should NOT be forced or a kid punished for it.
Give your son vitamins... he will be fine.
All the best,
Susan