yes, his parents are probably adding fuel to the fire. What he's going through is a stage that toddlers will go through several times when they are young and again when they get to be teens
If he doesn't want to eat at the table like a good boy, then let him down and tell him that he needs to eat at the table or supper's done. Leave his food on the table and continue to eat. He will probably want back up after a couple of minutes once he sees that everyone else is still eating. If he doesn't, don't sweat it. He won't starve to death. He'll start understanding that we eat when we are supposed to or we go hungry. And believe me, he won't want to go hungry!
Oh, and as far as the cupboards, why don't they put safety locks on them? It's also good to let them play with tupperware and pots and pans. He won't hurt them or get hurt by them. You just may have to to some more dishes.
The way the caregivers respond determines how long the stage lasts and how many more there may be in the future. My son is in one now. He has been acting up a lot lately. Plus, he has screaming fits when things don't go his way. I normally tell him not to act like that, and if he doesn't stop, I go put him in his crib and shut the light off and shut the door. I give him some alone time so he can realize that we don't act ugly like that. After a few minutes, I go in his room and ask if he is going to be nice. It works every time.