I wouldn't be mad if you did. When you really know/understand someone, their 'flaws' make you feel bad or like wish you could help, because it all makes sense. Honestly, it's the same thing Naruto said to Sasuke after the Danzo fight.
That is admirable philosophically, but here is the one flaw in this thinking. You say that when you really know and understand someone , you feel bad and wish you could help. However, if you don't understand that person or if you didn't even know that they had a problem at all, then all of their attacks on you would only seem random (like they are just being a jerk) and you would not know whether they are doing this because of some deep mental issue or just because that is simply their nature.
If you don't know this person, then even if the person does have issues, you don't know this, so the attacks on you automatically seem to be their nature. You can't feel sorry for a person if a person doesn't tell you their issues.
You may say that you shouldn't just assume someone to be a bad person, but you also shouldn't assume that they are good and just have issues either.
Either way, if someone just randomly projects their attacks on you, then nothing is getting solved and you just end up getting hurt!
There is a proper way to get someone to understand your feelings and that way is to sit down and talk about them. It is not to bring pain to other innocent people.
For someone like Sasuke, I'd be fine with talking to him and trying to offer comfort, but I will not take his abuse. Compassion is one thing, but just being punching bag for someone who may or may not have mental issues is different. The latter is just stupid!
I don't know whether or not you are one of those people who believes that nobody is purely evil, but I say otherwise! Therefore, if someone comes and attacks me, I will not accept and tolerate it! I'll comfort them if they simply talk to me about their problems in a civilized manner, but I will not take their hatred! I do not assume that every jerk is just someone with issues!
Finally, nobody has a right to hurt innocent people just because they have issues! Use your civilized words to seek comfort or keep your mouth shut! We all have problems!