First of all, when you're an Uchiha, all Senju are evil by birthright. Secondly, don't act like Tsunade was tryna protect Sasuke, she only did that for Naruto and because they wanted preserve the Uchiha bloodline for Konoha's Military strength. Thirdly, Tsunade can be blamed for her absence, if she hadn't ran away from the village like a and spent years drowning her sorrows like a crybaby, she might have become Hokage sooner and Hiruzen wouldn't have had to retake the post, that way his weakness and cowardliness would not have played a factor in allowing Danzo to fabricate the Uchiha revolution and massacre. Her actions affected alot of people and alot of incidents in that manner, she didn't take responsibility and action that befit her status and birthright like Sasuke is doing now, she was a cowardly crybaby and Sasuke is dealing with that now. Oh and the fact that Tsunade herself left the village for longer than Sasuke did and no assassins were sent after her would have made her a major hypocrite if she sent assassins after him. Having said that, I neither agree nor disagree with Sasuke in this manner, it is both justifiable and unjustifiable depending on what lense you are looking at, I was just pointing out what the other lense shows.