So if they grey beards, normal man races takes a life time, or approx 80 years to master the voice. So an Altmer who lives for 1000 years could master it in no time. Why then do so few High Elves use the voice, or is it because its the ancient nord art. Thoughts?

I pretty sure only Nords can learn the voice. The dragonborn is the only exception. Not sure though.

The Greybeards are somewhat selective in who they teach, it would seem. Would a group of Nords (monks as they may be) even want to teach an Altmer though? I'm not sure.

Add to that that Altmer... really aren't as amazingly long lived as they like to pretend.

I think it's mostly because it's a very Nord tradition, & that the Greybeards are rather picky.
They can hit a millennium just fine.
Unless you're implying that you kill a lot of them before that point, in which case I don't think that's fair criteria.

The Altmer probably think it's a lesser, human art and prefer their fancy magic instead

Why then do they not have FUS RO DAH in a spell for Alteration.

Probably.
It's probably a mix of the above + the Greybeards being selective.

If the greybeards are so selective how the hell does Ulfric stormcloak have the power to use the Thu'um?

Altmer are immoral their stupid thalmor and aldmeri dominion are destroying the empire that Talos made that's why elves should't be taught the voice by the greybeards

He was going to be a greybeard before the war with the aldmeri dominion

Oh? man after all the hours I played this game how did I miss the one piece of info I was always wondering about?

It's fairly easy to overlook especially if you sided with the imperials.

Am pretty sure kynetherth granted the voice to the race of men, not mer or bestials just man.

According to TES wiki, Kynareth granted the power of the Thu'um to "the races of men" but Paarthurnax taught "mortals" to use the Thu'um.

It's possible that Kynareth actually granted it to all mortal races, and that the history of the Thu'um was lost slightly along the way. Either that or by "men" it did simply mean the mortal races.

Or the Thu'um is only learnable in the way the Greybeard's learn it if one is human, but the Dovahkiin can be of any race and learn it as he/she does.

Or it's an oversight by Bethesda.