Should the players of a faction not be largely happy with the name of their own class?

Apparently not if you ask certain snowflakes and certain companys...

If I did, I wouldn't have the audacity to be mad when someone called me a dick-eater.

Fair enough, but would you rename yourself Dick Gobbler Dante? I doubt it.

Shout traitor all you want, but this is our class name.

Personally I don't gaf about your false emperor.

If I was as proud of gobbling that wang as traitors seem to be of betraying their own race and the Emperor, absolutely.

I gather that you get your perspective on the Chaos Marines from books where the main character shouts "For the Emperor" a lot.

Because in Chaos lore treachery is something that happens in the shadows. Weserve greater beings now (the opinion of Chaos Marines)

Well, chaos marines are traitors by definition, chaos is the enemy of humanity and indeed all sentient beings. Traitor marines willingly and often enthusiastically embrace the antithesis of -everything- hence, traitors.

Yes, but you are still looking at this from a Loyalist perspective.

From the perspective of many Chaos Marines (maybe not all, but a substantial proportion) they are the wronged party, attempting to open the eyes of their brothers to the true actions of their superiors.

The Thousand Sons, for example, were no more traitors than the Space Wolves. Less, probably. Actions outwith their control decided their fate.