I wonder about the ethical connotations of having Harry behave towards Snape exactly the same as Voldemort, i.e. torture him with pain and the threat of death in order to make him behave the way Harry wants him too.
It's a usual by-product of the power fantasy that the hero inevitably starts to use his power in a fashion extremely similar to the villain, but it's okay because the villain's were mean to the hero and thus had it coming.
The dating service stuff was decent - very much overly rational, especially when you keep in mind that most of the people involved in those conversations are 14 - but not bad.
It's not ethical, and if Dumbleodre or Hermione knew exactly what Harry had done, they would be rightly appalled. If it were anyone but Voldemort, Bellatrix, or Snape, even Harry would be ashamed of what he had done. So no, I am not saying it was right (it was wrong), just understandable If you stick to the story through to the end, let me know if you think Harry makes up for it a bit.