help me understand this

I`m reading a website about Animal Assisted Therapy.
I have two sentenses I can`t understand.
Would someone mind saying these in a different way.

・It is rude for a person to challenge another for walking down a public street.

・That it is natural for one dog to challenge another does not mean its polite.


the context:
Visiting dogs must be polite. It is rude for a person to challenge another for walking down a public street. The same is true for your dog. That it is natural for one dog to challenge another does not mean its polite.

Tank you in advance.

1. It is not polite for a person to challenge another person because that other person was walking down a public street.

2. It may be natural that dogs challenge other dogs, but the fact that it is natural does not mean that it is polite. (In other words, even though it is natural, it can still be rude.)

- Kef