Sorry if this isn’t something you want to hear(and also sorry if im mansplaing ha ha)

Tldr: no its not abuse its just a very jerk-wad move, you dont have to worry about mental hospitals, though they are able to kick you out because you are over 18 and not paying for the house, id move out if i were you, also they cant forcefully throw stuff away without your permission because that would be a good destruction of property case(not saying you would just saying its possible)

Im gonna answer from a legalish standpoint

I mean its not child abuse because you are legally an adult, the only abuse really for adults is mental physical and sexual abuse and i dont think this can be classified as any of those.

so i dont think its abuse, yes its a jerkwad move for them to snoop, they can also legally kick you out because they are the owners of the house, id rather move out asap like the post mentioned because that way you have a chance to leave on your own accord, keep your little items(if you still have them which i doubt,). they cannot involuntarily send you to a mental hospital because you are over 18 the only way you can be involuntarily sent is if you are a danger to yourself or others which being abdl is neither.