Interestingly enough, without that second statement (implied or otherwise), the first has little weight.
In a perfect world, when the DM says "I don't want X because I don't like it," the players say, "OK", and that is the end of it. However, people seldom find themselves in a perfect world, and often one has to make a decision between having the thing one doesn't like (or not having the thing one does like), and playing in a given game.
Do you honestly feel the only way to achieve a particular objective is through threats or ultimatums?
This again seems alien to me. An example from one of my longest running campaigns after a play'er character had died. It was an "epic story" style campaign so we rarely if ever brought people back from the dead the player was makign a new character.
"Hey, I'm thinking I want to go with something different this time... I want to make a 1/2 demon."
"Eh... I'd rather you didn't. The places you're in right now a 1/2 demon would kind of stick out... I'm not really feeling the idea of having to account for that all the time."
"Ah, that's cool, I can do something else."
No ultimatums, no threats, no demands... Just two people sharing their thoughts on what's best for the game.
A year or so later in the same campaign, higher level. The group had "split" into two... The evil characters and the good, (asame group two sets of characters alternating on a semi weekly basis.) Another character a cleric of vangal had died... But now he had a resurection cast on him by the paryy druid:
"Hey J, instead of the random roll, can I make a centaur?"
"Probably not.

"
"Here's my thoughts: Ok, so I'm getting to the point where I want to challenge Vangal's high priest to the right to lead his church, and I thought what if when sending me back, Vangal saw somethign in me, and "blessed" me with a new form... His church are the mad horsemen right? I'd litterally be a "Horse man..." and I'm hight enough level to account for the LA anyway..."
"Actually that sounds pretty cool... Let's roll with it."
Again... no ultimatums, threats or demands... Two people, with the goal of having fun rationally discussing their thoughts.