To be honest they are too stupid to be evil, i mean their terrible attiude makes any sane person dispise them, their methods are horrific, but biggest problem of them all is THEY WANT TO UNMAKE THE WORLD, which means expect a few elves they are against the entire world.

There is a fine line between bravey and outright stupidity, the thalmor sure crossed the line. Their ideal cause properbly any race (even dragons) to make enermy with them, because most nirm population want to exist. So the thalmor is against Dragons, creatures of every corner, any vampires, werewolfs or whatever, any people that want to live, dark brotherhood (they want to exist too), thieves guild, mage guild and countless other organisation out there.

The real question come into play is, how can an organisation that only give elven armor to their troops can magically form several aliances and cripple ,threaten tamirel? wouldnt their ideals cause all race to aniliate them in a flash?

Beating the Empire for a while in the Great war then the Empire giving in to their demands probably helps induce enough fear in the hearts of most people that they can do whatever they want. I don't think everyone knows they want to unmake the world.

1) They don't advertise the whole 'we want to unmake the world' as part of their campaign slogan. Chances are only the elite councils at the top are even consciously acting with that goal in mind, the folks at the bottom are acting for the glory of the Aldmeri Dominion and to destroy the heresy that is Talos.
2) Mer, as a general whole, want to escape the world, which would only put half the world against them even if they did advertise their goals.

They don't view the unmaking of the Mortal plane as bad. They want to undo it in order to be united with Auriel/become gods once again. After losing the knowledge of how to ascend without ending the world, the Thalmor decided to take a different route.

but surely the empire knows, just by annoucing the fact that thalmor want to unmake the world and you would have everything thrown at them at every corner. Besides the dragons are intelligent enough to know this, lorewise angrying dragons = sucide.

Also their attiude in game is just down right terrible, makes me wonder how did they even form alliances?

By offering people wealth in exchange for favors

my point being: their threating attiude and dominative expression will force everyone to a dead end, which only turns people back and bite them. heck most thalmor are forced solders, why dont they turn against the tyranny during great war?

Wheres the proof? you can argue that the Bosmer arent happy with it, but considering we havent really interacted with Dominion people all that much, and all the sources are written by Imperials: you cant jump to assumptions.

The Empire can announce whatever it wants - what makes you think people would believe them, or care? Half of Tamriel shares an Elven viewpoint (Mundus as a prison), and most people care a lot more about their daily lives than they do about some metaphysical goal. The Thalmor claim to have brought back the moons, without which Khajiiti physiology and society cannot function. That's a big reason to join their side, rather than the weakened Empire's.

Dragons weren't really around until this year. And with Dovahkiin killing them ll, they'll probably fade back into obscurity shortly.

I hate to Godwin this thing, but the Nazis really are good examples. The ideology was evil, but people still followed them and allied with them. Same thing with Communism, and a whole bunch of other regimes.

Source?

Runil and his journal gives great discription about living within the thalmor, besides their ruling method isnt pleasant at all

With the regimes you said, those express their manipulative nature and they all try to act good to win people over, thats why they were quite sucessful.
But thalmor's cunning isnt expressed at all in this game, in fact there is none about their deceptive nature, they seems like village idiots that would random attack people on sight. You need to win people over to win the war, well thalmor's attiude doesnt help at all.