But if you're gonna play Time Police and go back to undo the attack on the Kelvin (thus changing countless lives) why stop there? Seven million humans died when the Xindi attacked Earth. Proven tampering from the future. Let's undo that. What about that entire colony killed in ENT: "Shockwave"? Many big historical Trek events are rife with tampering from future aliens. Some had halfway hack-job fixes (the Xindi attack left seven million humans dead that shouldn't be, many were killed in the First Contact Borg attack, microchips are supposedly the result of a timeship from the future that crashed in the 60's) Yet much damage was left unfixed. Same thing in STXI.
And I'm still waiting to see that, because it really should have been
undone. But I regard ENT as being an alternate timeline anyway. The Klingon from the pilot episode was not supposed to be there, he was part if the TCW, then there where a couple of big events of which was said "this should not have happened", and then there were the remains of First Contact. The entire series is not in the same timeline as TOS, TNG, DS9 and VOY. Which is why Riker is much fatter in ENT: TATV compared to TNG: Pegasus.
At the same time ENT is evidence that in the Star Trek universe there is only one timeline. In "Shockwave", as soon as Daniels removes Archer from the 22nd century and transfers him to the 31st century, the timeline of the 31st century is instantly fucked up.