Honest question, as I am unsure of what the law is regarding such a circumstance. If somebody steps in to defend someone who is defenseless (such as a child, disabled person, or an elderly person), is that treated the same that self-defense would be in court, or is it considered illegal? If it is currently considered illegal, should it be made akin to self-defense?

its legal.

Okay, good. I thought I was going to have another instance of losing faith in humanity. Gotta be optimistic for those few bits of faith remaining.

depends on what it means to "be a good person"