@flannan
All science is 'bogus'. Science is just the study of how we perceive and replicate events and structures both in their naturally-occurring state and in a relative vacuum of controlled variables. People harping on it like it's the absolute truth are practically just scientific religious-zealots. But, that also means that
until we get better information, it's as good as true until then. Neither here nor there, though.
That said, no. There's too many examples to choose from where that's not the case in real life, but that'll start a severely off-topic argument I don't feel like having right now - I'm fairly hangry, after all.
But for settings like this, where we have actual nobility, that's definitely not the case simply because who's going to 'catch and eliminate' them? As I stated, they make themselves
necessary before they get complacent and just get obvious with their corruption, because it's a thrill at that point - no one can touch them, they've proven it hundreds, if not thousands of times before we ever get to their oily hides on-screen. Their only superior tends to be an autocrat, a wielder of technically absolute power who MUST defend them if he doesn't want to destabilize his power structure and thus the kingdom/nation, causing untold social and criminal issues, and a great deal of death from all sorts of factors.
As I also stated they tend to come up as a bunch of fellow jackasses. Either allied noble families, or those who've been pressganged by the intrapolitical climate, or a House who owes too many favors - down to sponsored Houses who can't let their benefactor be fucked over. You don't get obvious and stupid without making sure that all anyone can do is just grit their teeth and cry while you do whatever you like to them. In many settings, and many times in real life, the supporting nobility held power second only to the monarch - or sadly enough, in excess when speaking practically. Landed nobles were essentially lesser kings who paid tribute and servitude to the greater king of the whole nation. A single king can't rule a large amount of land and people by himself, after all - so the nobility were those who ruled in his stead outside of his reach from the Throne. Which means the Crown literally relies on them and needs them. Quickest way to subvert that is to eliminate all competitors who aren't going to play the game your way, and now you present a unified front against the Crown and can easily pressure it to do what they like or else... well, it's not going to be pretty.
I doubt that'll factor heavily into what's about to come up, but keeping this in mind, it makes perfect sense. After all, he's doing this in broad daylight and all anyone can say is 'we can never go against him'. He himself, is obviously in no way a threat. So what are they afraid of? His levies? His bannermen? No, because if he used his forces to attack people just because, that would call down the wrath of other nobles and the Crown itself. Ergo the only reason a noble can be so utterly terrifying is if there's nothing the other Houses or the Crown can do about it, or if they're in cahootz. This isn't some border town, after all, it's the capitol. If the king and other nobles were powerful and just and wanted this guy gone, he would simply be gone. But he's not, he's about to kidnap a girl and rape her if not stopped. Just one in a long, long line. So clearly someone has his back, and going against him is the same as going against someone much bigger than him.
So I don't see the 'corrupt noble' in fiction as a trope or something to be decried. It makes sense. Finding an abundance of good-hearted, just, and fair nobles in fiction is typically only done when it's the 'good nobles' vs 'the bad nobles', or else it's just a total wash and reeks of wankery.