(The below is 100% personal opinion)
The tactic being employed by the Baron De Skelped Erse (and his plus one) is very similar to the strategy used by opponents of Scottish Independence.
"You had a referendum in 2014. We answered no. ThAtS DeMoCrAcY So YoU CaNt HaVe A sEcOnD sHoT"
They claim a second referendum can't ever happen because democracy. It's makes no sense at all. Surely, democracy allows for minds to change over time? I mean, by the same logic, we might as well never, ever have any more than one election. 'The people got to choose the government way back in nineteen canteen, that was democracy, so no, you don't get another election'. Nonsense.
So, in the same gaslighting manner, Baron Heed-da-Baw is hinging this whole thing on the idea that the Historic Compromise must be permanent. Really permanent. Never to speak about anything to do with it again permanent. Which... is nonsense.
Just like the Scottish Independence referendum, opponents like to say "it was supposed to be once in a generation!!!!". But, they refuse to accept the fact that the material circumstances have changed since the first one. (in that case, Brexit happened).
The Historic Compromise, no matter how long it lasts, is still an Historic Compromise. It is utterly unfair to say that it not a compromise because it can't come with a future-proof guarantee that nothing about the monarchy ever gets mentioned ever ever ever again. It is not only unfair, it is bad faith. It is not only bad faith, it is absolutely and terrifyingly UNDEMOCRATIC.
You want honesty? Ok. The Historic Compromise will last as long as it lasts. That's as confident an answer I can give without being able to read the future. It will last as long as it lasts. However, I am confident that the side that breaks it won't be us. Supporters of the Historic Compromise will live with it and stand by it all the way up until the other side does something silly to force a material change in circumstances.
A major principle in governance is that one Parliament can't tie the hands of a future Parliament. So, the Baron Von Bawlsax is asking for the impossible by demanding the compromise comes with some kind of guarantee that nothing in the future ever gets mentioned ever again regarding the monarchy. Like, what if we did find some way to make that guarantee and then a King decides to just start abusing his side of the system in some way? Well, we would just have to accept it and let him get away with it because, well, democracy had its day and the compromise is to last forever plus a day.
Well, no. The historic compromise will last as long as it lasts and it will only be broken in the event of a change in the material circumstances surrounding the Monarchy. Demanding anything further, again, is absolutely and terrifyingly undemocratic.