We go to planets and destroy the inhabitants in there. Doesn't sound good to me

Technically, we are evicting invaders - not inhabitants. We were told that the Fallen invaded Earth, the Hive were given the Moon in hopes of keeping them off of Earth, and that the Cabal are invaders, by their nature. The broader question is if our motivations are representative of what is ultimately "good" or "evil". Right now, we do not know.

But if you heard stories the guardian was suppose to be the evil

We have seen speculation - both in-game and here. I've even speculated on here about how we are being manipulated. But, being a pawn does not make one evil. Sure, the Traveler might be evil - but it could also be that the Speaker is the embodiment of the evil. Guardians (at least our Guardians) have no evil intents - at worst, we are ignorant and at best, we are being misled. That still does not change the fact that the human race are the innocents, most likely. Those were the people that lived on the rest of the planet, had established bases on the Moon, had colonized at least Venus and Mars - and were consequentially victims of mass genocide by occupying and invading forces. In the end, even if the Traveler is evil, so are all of the other non-human races (excluding the Awoken, obviously). Assume that the Traveler is proven to be evil. It was represented to all of humanity as being good. Humanity had no complicity in the plans of the Traveler, and is yet another victim in its travels. For all we know, the reason for the terraforming, in the first place, is to create habitable worlds for occupying forces. But, the fact remains, that there is just no justification for genocide. So, no matter the outcome, all of those races are evil as well, then - apart from the only real victims in the game, which were already eradicated. Then, you are just dealing with varying degrees of evil. I've said it before, and it is worth repeating. At some point in the next ten-ish years, the Tower will either no longer be our home, or will no longer be safe refuge for those who pledge allegiance to the Speaker. I really believe that the Guardians will eventually become our enemy, and we will become allegiant with the views of the Awoken and the Exo Stranger.

No we are the evil