But also steemcleaners are wrong sometimes, and they make some mistakes!!
Do they take the resonsibility for this wrong things also??

Yes, they do.
Contact them via Discord, tell them "Yo, the source you gave was wrong." (par example) and they will edit the comment and remove the flag.

Where is that person/or institution, which can decide, what really is plagiarism, spamming, or somethin else???
I dont need something like that here!

Steemit means:
The rich person has the power. Steemcleaners is rich.
Steemcleaners can downvote up to 140$. Steemcleaners will do that, if necessary.

If you don't want that on Steemit then I have to say that you are in the wrong place, sorry.

Furthermore, anyone has the right to flag anything and anyone.
"Disagreement on Rewards" is given as a flag reason by Steemit itself.

Steemcleaners is a collective of people who give/delegate their SP, because they disagree on rewarding plagiarizer, spammer and ID thiefs.
Whenever SC flags wrong - mistakes happen, they're human - they redact the flag as soon as they hear about it. However, if you just take a news article and paste it here on Steemit and then expect to be paid (in SBD) for that, then you are mistaken.

On a personal note:

May I take your "Lotto Cats" and publish them as my own and even get paid for that in SBD? Of course not! It's yours! Just like the news article is property of the newspaper! He has no right to take it and resell it. That's what @Steemcleaners go against. They punish those thiefs.
And when the text matches in a 1:1 ratio - then, of course, this is as clear as it can get, that this is stolen content.