I can see the "little boy" in him. He knows how to press sentimentality buttons, not only because he is trained to press buttons to elicit useful responses, but I believe that the "teddy bear" thing you referred to in another post is really part of his character. I can see that (I don't know if others see it or believe it is there).
But I think that the "thug" side of him is far far more important. So much so that the other aspect I just mentioned seems hardly worth mentioning. Certainly not as a way of trying to see the good in someone who is...well, just read Mark Bakers last post. BTW, I haven't seen the car door incident, but I don't think a situation like that (as described) is all that important because zillions of people do things like that under provocation etc. The thuggery I think of is what he did for the cult, some of it described/confirmed as gag order procedures. When he said that what the stuff he used to do, there was no comment of regret, or how bad it was, or how nasty to victims. Why? Because he only wanted to support Debbie to attack Dave. He did not say the actions were WRONG, because he was applying LRH policy and there is no reason to think he would not do it again. Has he said he would never do this shit again? He was just agreeing that the mechanics were as stated.
I'm starting to ramble a bit. My main point is, I don't know if its true that people do not see different aspects of Marty's Character. I think they do but they think that his thug elements are still way too much of a serious ongoing purpose to be bothered about the goodness there may be in him.
FWIW. I think people see the complexity of Debbie too.