interpret or view (something) in a particular way.
Understanding does not mean you would do the same thing. Understanding mean you know why someone did something and have rationally connected their thought process. It does not necessarily dictate that you would do the same thing, merely that you are aware of how they came to their actions or reasoning. Like how in Watchmen where Dr. Manhattan told Ozymandias when he nuked New York "without condoning, or condemning, I understand." Dr Manhattan was aware of why Ozymandias was doing what he was doing, but he would not have done it himself.