Yeah I agree with you on this, as also someone who reads Himo/Sponger.Unfortunately for you, this isn't that kind of story. In fact, it has a lot more in common with Risou no Himo Seikatsu, only instead of starting at the very top as the queen's consort, MC has to work his way up from the bottom as the adopted son of one of the lowest-ranked nobles in the kingdom.
(I love the part in that story where the queen is apologizing to the MC for breaking her promise of keeping him from getting caught up in their politics, and then he cheerfully tells her that it's fine - he knew that was a promise that she wasn't going to be able to keep at all. The queen's shocked expression was absolutely priceless.)
Also, I don't like most of those revenge-porn stories because a lot of them completely gloss over the consequences of the MC's actions. Where as with stories like this one? It's all about the consequences.
Sorry, but if that's not to your liking, then you may wanna just drop this title and find something else.
Every story isn't about fighting the injustice or taking down corrupted individual.
There are various aspects one has to consider before taking action, and have to present situation to avoid any conflict.