Bullying in clubs of artists, in art clubs and at exhibitions, very bad bullying,

I am a member of 4 clubs, including an art-club (amateur painter) I paint myself pictures (in acrylic) and sometimes put my pictures out to expose. What I would be interested in: do you (possibly also artists / hobby artists / club members) also have the impression that in the clubs they make a very nasty ,very bad bullying ?
There are several examples. I presented an image on an easel at an exhibition. Promptly image and easel was pushed into the corner, by "UNKNOWN". Another time, a decent blob of jam was on one of my pictures! And these were not kids who did that. : Mad: : Mad: : Mad:
When someone asked for me to buy a picture,
...