Saying how you want the campaign to be and dictating what methods the PC's use to solve the challenges presented are two separate things. If everyone wants to play court intrigue, the PC's should be allowed to approach that however they want to.
The DM sets up challenges, not solutions. It is not the DM's job to dictate how the players will solve their problems. That is called Railroading. If you, or any other DM, thinks that a DM should say "Ok, everyone gets one cantrip, and you are only allowed to use that one cantirp, I don't care what class you are this is the cantrip you have to use every time during combat. Also, you have to use diplomacy and intrigue as often as possible, otherwise I won't have any fun. And I want you to do it like upitty lords. In fact, all of you are lords of your own fiefdoms, but I'm going to dictate what your product is for each of your fiefdoms. Oh, and make sure you use these lines while playing, i've got some zingers I want you to use and I love witty banter."
That's bull, and it's the same thing as saying "Well, guns are obviously better than every other type of weapon, so I'm going to make sure they're really, really good, and give one shot KO's, to make sure my players only choose to use guns as often as possible, because I want to play a game with lots of high seas battles with guns and that's the image I want to see, and if they don't use guns then I've failed as a DM."
If they don't use guns they have simply found something they want to do that is more fun to them, and that should be perfectly fine. Sure, they'll miss out, but they may find a better way to solve the problem. Or a way that everyone will be laughing about for years.
The DM can create a setting. The DM can set up challenges. The Players get to solve those challenges. Otherwise, you may as well go play with dolls in your basement, cause then they'll do exactly what you want. The game is about the player's fun. The DM should have no stake in how it plays out other than to give opportunity for the players to shine, or die if the dice says that's what happens. And while I have DM'd quite a bit, I'm talking about this as a Player. I've played with DM's who want things to turn out a certain way, and shut down every attempt to go outside the box by simply saying "Your Warlock's Devil's Sight cannot see in this darkness because there is absolutely zero light anywhere in it so it couldn't possibly happen," and then goes off on a tangent that really boiled down to "he didn't know I had that ability and it would ruin the trap he had planned and he really, really wanted that trap to go off."
And I've played with my brother DMing, where he throws something at us and when we shrug, not knowing what to do, he shrugs back and says "Figure it out." He lets us try anything. Sometimes it doesn't work, and sometimes it does, and when it does, it's always awesome. He doesn't even know all of our abilities, he doesn't set challenges to match what we can do. He's written an entire campaign full of awesome quests and side quests, and never does he actually ask what we can do. He simply gives us a challenge, and we have to figure it out. If I can see in the darkness, wonderful! I can get past that trap. If we're in the hold of a sinking ship and there's someone on the other side of a closed door, stuck as water is filling it up, and I use both my spell slots to cast Dimension Door twice to save him, completely bypassing the entire problem (but using up my slots, which put us in a bad situation later), then great! I figured out a way around the problem! He didn't "Want us to do it a certain way", he wanted us to use our brains and get through the problem.
The DM is the console. He designs the world, creates NPC's, sets up challenges and provides an opportunity for the players to play out a great story. But in a game where one person has all the power and can dictate the entire world, the only thing the players can choose is their characters. The only actions they can control is their characters'. Take away that agency, start dictating how they should be playing, and you've overstepped your bounds as a DM.