I’d say you’re fully within your rights to set the rules in your own home. If you don’t want him to get up from the table with jelly hands, have a damp flannel at the table for him to use before he gets up.
I am like you, Klara. I believe that making children aware that their behaviour is unacceptable without being reactionary is vital. Create realistic and viable consequences and stick to what you say. That behaviour is him crying out for boundaries because they are a sign of love.