Hello, paclmaya! I was asking myself the same question a few times already.
The Jupi Casino is quite an impressive example, and I agree one can feel truly misguided. Keeping that in mind, we aim to present all considered factors and warnings alike on the proper tab called reputation explained:

Additional explanations are hidden under the "i" icon.
As SunsetGaze mentioned - good thinking again - the number of unresolved complaints granted the casino many black points that are directly affecting the rating.
I'm not pretty sure how the complaint process works elsewhere, for us, it is a strong source of information we would not normally gain, hence we see any complaint as an opportunity to check the casino's score.
Some penalizations are applied automatically, and some are, on the rather hand a subject of long debates. I can assure you we're constantly trying to evaluate the casino's rating. If we come across severe pieces of evidence, the special call is settled to ensure the score still fits. We always try to reach out to the casinos to present our advice or point of view, so it's not like we decrease the rating without further notice. There are, however, some casinos which already failed to respond, in such cases we may prefer to lower the rating in advance. The thought is quite simple if the casino isn't willing to cooperate it's safer to adjust the rating or add the warning, so players can decide whether they are willing to take a risk. I hope I succeeded in providing an honest explanation 🙂.
It's not easy to find a fair balance while you try to consider all possible effects of your decision, still, we try hard to maintain this reasonable, constant balance.
If you feel I missed something, ask away, please.
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