Those who lay down with dogs, wake up with fleas.

If botting is a bad thing to you and you start overlooking the action for a friend's sake, then you may find your moral compass shifting to start accepting the behavior from anybody and you might even start doing questionable things yourself. On top of that, the knowledge you hold of your friend doing something questionable and your inaction to stop or report the behavior also makes you a culprit.

So, yeah. You are really no better than a botter yourself if you knowingly let somebody bot, regardless of who they are. Since this is just a game and there are no real life implications, it is up to you to decide the identity you want for yourself in a virtual world.