Do what you will is the whole of the law for your game.
Otherwise, I am sorry but -- like football or figure skating or whatever else you might undertake to dislike -- it's not about you. The people who like it are as entitled to it as you are to the things that you like.
And I've never said otherwise. I'm pretty sure the argument has been the other way around - that the approach I prefer in the game isn't acceptable from someone else's point of view (or isn't 'logically consistent' as the argument might be.)
I reckon that if a foolish magic-user can discover how to summon one in the first place, then slightly less foolish adventurers can discover what they need to know about the lair of Dreadgore the Demented and the Dweller in Darkness before they invite themselves in.
That's one assumption. But... not one that always holds true.
I mean, how many possible monstrosities can a bad guy summon? This expectation that PCs should be able to pinpoint precisely what resources an enemy has and what monsters they will fight - that players are "foolish" if they are not capable of knowing in advance what they will be encountering - really is not an attitude I agree with.
I think there can be games that are about that level of investigation and some sort of battle of wits between the players and the DM. But I don't think that is, or should be, true of every game. And I think there remains many, many legitimate reasons why PCs can - and often will - enter an encounter without knowing exactly what they are up against.