Renegade isn't necessarily *evil*, exactly. It's a shoot first, human-centric, "whatever it takes" mentality, as opposed to the paragon diplomatic, obviously not pacifist but shooting is more of a last resort, "there are lines we don't cross no matter what" mentality. (Example: people love Buzz Aldrin for punching the reporter who was harassing him and his daughter about the moon landings being faked, and nearly every player I've talked to snaps and punches the annoying reporter who deliberately paints the main character in the absolute worst possible light at some point in playthroughs. Clearly a renegade option, but not one I would consider evil.)
Which is more evil: unleashing a race of insectoid aliens that had terrorized the galaxy and the galaxy had banded together to eliminate once before, at great cost, on the word of a queen promising that they would behave themselves, no, for real this time; or killing the queen and the surviving children to prevent them from destroying everything? Leaving them trapped where they are is not an option because plot reasons. You get a lot of choices where there are valid arguments on both sides, and which one is right depends on whether you believe that the ends justify the means or there are certain things that can never be justified.
Of course, a lot of times, renegade options are an excuse to play Shepard as an asshole. So there is that.
(Worth noting that Saturday was N7 Day, an annual celebration for Mass Effect fans, and this went up on Patreon Saturday.)