And what is the problem with that? You actually think that vassals should stand idle and watch one of their fellows be striped of all titles, castrated or blinded and be devoid of any opinion on the matter?
Rebels are rebels. By rebelling against the crown, they are putting their life on the line. In feudal societies, a civil war was a split, the defeated tended to lose a lot.
eg: Williams Harrying of the North
In the ERE even more so. When the Komenos lost the ERE throne, they did not become vassals to the new dynasty - but independent.
also:
Castrating and blinding is limited to the violent ERE(Greek culture)
Your vassals don't care whether you throw others in prison and keep them there as long as you have a reason, I seem to remember a bohemian king: Wenceslaus IV in a similar situation. He was imprisoned by his vassals who disliked him. The HRE lords didn't seem to care.
Ransoming is very much the epitomy of respect. It was how a war economy worked. In fact the biggest complaint on the battle of Agincourt was that the knights were all slain by the longbows, so there was no ransom money. Ransoming is respectful.
This will not change. If you were putting your land and life on the line when you rebelled, how often would you rebel?
This is to ensure the vassal management game is a consistent hassle, and is not particularly accurate to the real world. England suffered one or two civil wars to "lower crown authority" (
First baron's war) and had far more claimant wars (Stephen v Matilda, War of the Roses).
Being non-respectful to vassals in CK2 leads to tyranny, unless they are not of your religion (and your vassals allow you to change the revocation laws) or you are Greek.