A Man's Best Friend

Recently I stumbled across a saying that I hear and see alot but was very confused about, and that is "A Dog is a Man's best friend". Because us as Humans have the tendency to critisize others, be racist, back-stab, commit crimes and murders etc. Dogs are the other hand are very loyal and will protect their owners despite their size. Dogs, unlike most people accept the owner for who they are. It doesn't matter if there is something wrong with you, the only thing a dog sees in you is that how much you mean to him/her. The reason I chose to look into this is because I was wondered if every single human were to be as loyal as dogs, then how much better the world would be. Why is it that humans have to treat others differently because of their differences? is it to make them feel better about themselves? Although I am not a dog lover, I think the job as Man's best friend and to treat them with the respect they deserve is an important one.