It means that when dealing with things, we should stay out of it, not affected by environment, position and subjective and objective factors, and handle things fairly and reasonably like a bystander (like opening God's perspective). You can't stay out of it, because sometimes it will be like a mess and you can't start.

The speaker is in the middle.

It means that people who give advice to others should put themselves in the other's shoes and think about what they would do if they were in this situation, instead of taking it for granted without knowing anything. This is extremely irresponsible. "It's easy to stand and talk."