In the past, when I've been working face to face with people + spending all day with them, I have seen quite fundamental changes in some really far-gone people (Mike, Candy, Armanii) - without even arguing. I realised in dream that it was because of leading by example, I suspect this might actually make loving a bad person have a good element - because it introduces the bad person to love, and shows them that way - my technique before had always been to cut out their support to force them to re-think and, if needs be, basically pin them down and bombard them with my logic, that was a lot of hard work, and I still keep that option open to resort to if I have to. Bad people don't deserve love (at least as much) but some sort of inverted karma might be what gets the ball rolling - once they are better, they will listen and consider worded comments more - beforehand these people had been out of my grasp.
On the other hand, these people need challenging to change, maybe, but maybe at a later point where they'll consider it
I cannot bring myself to genuinely admire that nature though, nor can I afford to, but I can still act a little + with the good people around me, I don't have to direct a happy approach towards the bad person, they just have to see it, and see the power of friendship.
Thing is, when my dad picks a (worded) fight with me, I have to defend myself, I suppose he is one who I couldn't lead by example - and he sees himself as the leader I think anyway, and he just wouldn't be challenged if I pretended to be what he wanted me to be