If Ashley had let two princesses get torn apart by an angry mob of rebels, there would be such a massive reaction that either the rebels would be crushed and purged instantly or a civil war would erupt. There's no way it doesn't immediately escalate to the capital filled with knights and soldiers, and further violence immediately.

Then again, I don't really understand the strategy of a future king fostering an anti-monarch rebellion. As they've shown, there are two factions, and both want to bring down the monarchs. Nobles want to remove all competent royals, and install a powerless puppet king. The commoners want to kill the royals. So...ML has no faction backing him up. A competent noble could probably manipulate the rebels into supporting the nobles by painting themselves as different from the royals (just like modern politicians that convince working class to vote against their own interests).