You can always submit a ticket here Commander: 

Plarium Support Center  

I'm sorry general but I don't do that anymore because I get the answer please describe your problem in more detail. I did that and still I get the same mail again. sorry if I have to say that now I feel fooled.

Sorry to hear that Commander but they are the only ones being able to change it if they want,

Yeah I turned mine off, I don't want people to be able to see if I'm online or not.  

and it will be not better after i delete all my friends and deinstall the plarium app

Correct. Just turn it of as in my opinion it has no added value

for me i would like to see who is on from my clan right now. otherwise I always have to ask

and not everyone wants to tell that

That suggestion has not been approved by Devs long time ago

but why is the friends bar in the plarium app even there?

I think because of the interactions between friends in the game, Commander.