Some people don't like loudmouths, but in the UFC, a loud mouth proves useful. Granted, it can backfire if one takes a shot at another fighter and then suffers a grueling loss, but in terms of elevating themselves to bigger and better fights, it does help to run one's mouth to a certain extent.
Why should anyone have a loud mouth in the UFC? Many people embraced the technical aspects that come with an MMA bout a long time ago. Once that embrace came, a respect for fighters who took on all comers came with it, and that respect stuck.
However, the fact remains that in the UFC, the heads still like when their talent just asks for fights, especially if the talent in question feels someone makes for a stylistically pleasing bout or an exciting bout for them. Therefore, for someone to possess a loud mouth and start jawing away at one guy or another, it shows UFC president Dana White and matchmaker Joe Silva that person wants to fight.
In other words, it makes their jobs easier. When talent turns down fights, it not only creates difficulty in finding people who wish to compete against a certain foe, but it also instills a doubt over whether or not some talent still shows a desire to fight, even if they don't talk retirement at that moment.
While people don't necessarily need to run their mouths like a Tito Ortiz or a Chael Sonnen, they do need to show that they will fight "anyone, anywhere, anytime" under the UFC banner. Preparation and all of the other factors that come into the subject of competition remain important, but desire proves key in finding UFC success.
Consider this food for thought, just in case we hear of another case of someone either not wanting a fight or not feeling close to what they'd call "ready" for a fight in the UFC anytime soon.