What bothers me about your approach is that you completely ignore the fact that the player is not the character in determining the outcome of social interactions towards them only. I'm fairly certain that you allow stealth checks against the players' WIS (perception), but I fail to see the difference between that and refusing to allow intimidate checks against their CHA. Telling a player that the orc has successfully intimidated their character isn't telling the player what to think, it's telling the player what constraints his character is under, much like not telling the player about the thief sneaking up on him that his character hasn't noticed yet. The player still has his entire agency to declare his actions knowing his character is intimidated by the orc. It's just more information about the world and the character the player is playing, it's not telling the player how to play, it's not telling the player what the player is thinking, its saying that this orc, in this situation, scares their character. What do you do about it?
I do not think the DM is entitled to say how a character thinks and acts - in your example, "scared" of the orc. I think the player should decide that because I consider this an example of the DM infringing upon the player's right to determine how the character thinks, acts, and what he or she says.
Whether or not the PCs notice the sneaking monsters is a different story because it does not infringe upon the player's right to determine how the character thinks, acts, or what he or she says. The point at which I'm making that check, the players have already declared how the characters are acting. In this case, keeping an eye out for hidden danger (otherwise, there will be no passive check). I'm making the Stealth check to determine how well they do at that effort.
The way I see it is that you've critically undermined your position as inconsistent by admitting that you would tell a player what their character thinks when under supernatural or magical influence. I'm pretty sure that when a character fails a will save against a fear spell that you tell the player that they now have the frightened condition, just as I'm sure that when a character fails a wisdom save against a charm effect that you tell the player that their character now considers Bob the Vampire Lord their bestest of best friends.
I would do what the spell says happens, yes. I don't see how following the rules on this point undermines my position.
So, you've established that, given proper circumstances, you've no issue informing a player what their character is thinking. However, you seem to be adamant that one should never, ever tell a player what their character is thinking when targeted by a social skill check, but you haven't yet established what makes those mechanics different from the spell mechanics.
So, point blank, why are social skills (mechanics which target numbers on the character sheet) inherently different from magical mind magic (other mechanics which target numbers on the character sheet)?
I'm adamant that nobody should do that to me and that I would not knowingly do that to anyone else. If you and yours go in for that sort of thing, you should definitely keep doing it. I'm not telling you how you or anyone else should play.
As for why social skills are different than magical compulsion, that should be self-evident - it's magic and it's the exception that proves the rule. But also because of this part of the Basic Rules I've already referenced upthread from the Roleplaying section of the Social Interaction entry (page 66):
"Roleplaying is, literally, the act of playing out a role. In this case, it’s
you as a player determining how your character thinks, acts, and talks."
This, taken in context with the basic conversation of the game (page 3) and the rules for ability checks (page 58), tells me that when an NPC tries to deceive, intimidate, or persuade a player character, the player determines the result, no roll. And so that's how I run my game and prefer other DMs handle it when I'm a player in their games.