You are aware the whole reason we choose to pursue Blackwall is because we think he his Blackwall. I mean, unless you knew he was an awful person putting money above human life the whole time and still wanted to bang him.
This is key. It does not matter how many times he tried to push the Inquisitor away, because we never know why he is pushing her away. For all I know, he could have seen something really bad fighting heroically as a Grey Warden and it left him unable to express himself fully. We never know the extent of his crime. We never know his real name. We never know who he actually was or what he actually accomplished. We think he is who he says he is, and he never says otherwise until after you have sex with him. You fall in love and have sex with the man whose persona he adopted, not Thom Rainier. I would never have slept with Thom Rainier.
Yes I am, and also Blackwall/Rainier is well aware too. Putting it frankly- all I see at this point is just a large amount of wounded ego hidden behind false morality.
I -not my Inquisitor, but I- was totally in love with what I thought Blackwall was, i.e. a romanceable Duncan. I howled at the moon for about two days in deep frustration after the revelations quest and in the end I felt I admired him even more for the man he really is, and realized I still loved him.
About all the 'put money above human life' and 'he did nothing to save the puppy' I take the freedom to laugh loudly. We are playing a game in which we constantly kill a lot of people, not just monsters, but also people, but hey, they are very bad people and then they are surrrounded by a red circle so they are enemies 
And no, don't tell me they attack you first because a lot of times I encountered bandits and such and kept at a distance, they ignored me such as dragons do. In my first and only run (still have to finish it) I have killed only one dragon and you know why? Because they don't attack me and they are magnificent, I just killed the one in the western approach because she attacked and I wanted to try my party at it.
I also never killed a druffalo in order to complete a quests because they are huge peaceful plushies but I bet I'm rather alone in this.
As I have already written Rainier accepted a dirty job but he was just the weapon, not the brain behind the kill, and if he refused to do it Orlesian nobility wouldn't have stopped their Grand Game and the noble he was sent to kill would have died by the hand of another mercenary. Did you keep Zevran in your party in DAO? He killed people in cold blood repeatedly and without remorse, he was an assassin, and Leliana keeps slitting throats in front of me and there's nothing I can do to avoid it. Oh and also Leliana LIED about her identity in DAO, she's not at all a lay sister of the Chantry but A SPY, a bard, an assassin who played and enjoyed the Grand Game.
So why don't people hate her too? She lied about her identity and put money and personal enjoyement above human lives a lot of times.
The only difference I see with Rainier is that he highlights his one and only fault, this way he makes himself vulnerable to people's judgement. Now I'm sure if he just said 'Yes I was payed to do a dirty job but I messed it all up, so what?' people wouldn't feel free to pillory him but would think 'oh he's such a naughty badass'.