One definition of understanding is sympathy to other people's problems. There are a lot of problems people have which I understand, have empathy for, but which I don't agree with.
To understand a person's problems that stem from their choices does not mean I have to agree with the choices that put them there in the first place.
For example, I understand that someone with an addiction needs their fix. I feel absolutely terrible for the suffering they go through because of their addiction and yet, I don't agree with their choices that put them in this situation.
There are many social problems that we face as a society which I understand and yet I don't agree with the choices of the individual which drove them to need my understanding. They don't owe me an explanation and they don't deserve to be treated unfairly but at the same time, they also don't deserve to be given special privelages and their rights should not come above mine.
We spend too much time sometimes understanding and too little time addressing the actual problems. So yes, we need understanding. We also need solutions that don't effect everyone else.