Interesting. I've noticed the same thing.
The more to the "straight" that a guy seems to be on the sexual orientation continuum, he more moaning and verbal he seems to be.
I like to moan and say lots of shit while either getting head or getting a fuck, but I'm noticing that seems to turn guys off so I just keep my mouth shut now.
The only time the verbal seems to add to the scene is when I'm deep screwing a guy from behind. I've got his legs spread wide, and my left arm over his left shoulder and grabbing onto his right pec. I've got my right hand down between his legs frigging his meat, while I'm working my hard dick deep into his guts. (This is another reason why I like "pocket-gays" for subs.) I'm usually sucking and licking on his neck and carotid artery. That's when I whisper in a deep throaty voice some kind of nasty little something into his ear. I slowly long-dick him, and whisper "Right THERE. That's where I'm gonna cum." when I'm balls deep. Then again with a long, deep stroke "Right THERE." I may "work it", and whisper "Feel the ring?" After a little hammer fucking, I'll give him a few slow strokes and whisper "You're such a good boy. Good boy." I may check in with him and whisper "You like that baby? You like getting totally fucked in that hot little ass of yours?" The response is always at least a "Yes".
Depending upon how long we've been fucking (in the context of weeks, etc.), I may start to elicit more commitment from my sub. That's when I may whisper "That's my ass, baby. Your ass is mine. Who's ass is it, baby?' The answer, how quickly and how soulfully it is offered is telling. If the answer comes quickly and soulfully voiced "It's yours" or "It's all yours" or "It's yours, sir", then I know that we're really bonding and the relationship is getting deeper.
About 1/2 the time, I want my subs to cum first. I want to feel them cum while riding my dick. I may or may not choose to cum depending upon whether I want them to feel psychologically and emotionally fulfilled by having me cum and close the pleasure loop with them. Or, I may choose not to cum, and leave them in a state of yearning despite their own physical release. They usually wonder if they did "something wrong". I reassure them that they didn't. But it still leaves lingering sexual tension which can lead to a more intriguing and romantic relationship. I may also have them suck me off.
I don't mind if my sub moans and expresses audible signals of gratitude and appreciation, but I do get distracted by too much verbal feedback from my subs. Depending on the mood of the scene, I may either "Shhhh, baby! Just enjoy the ride", or I may give my dick a good hard stab and say "Shut the fuck up!" For those subs who just can't keep their mouths our audible emanations to a level which is pleasing to me, that is when my right hand goes over their mouth or I get out the gag.
Sex is like playing the piano. You do need to hear music in order for the experience to be completely enjoyable, but too much racket is annoying.