The word "kid" has been used by society for a while. And you said it yourself. Kid means baby goat. We aren't exactly CALLING our children baby goats, in general. It's a bit of an analogy really. Kid is to baby goat as kid is to little human.
When our parents and random people off the street call us kids, they aren't referring to goats. They're saying we're small people. As if likes little goats. They don't MEAN to. Hell, half of the nation doesn't know kid means baby goat. They could care less. It's one of many labels of a child.
And the word "bitch". Is what you make of it. Your point of view makes it a bad word. Bitch can be used in a regular conversation with anyone of age, and one of the many will make a crack about a curse word. Words have multi meanings. Like kid=baby goat/a child, and bitch=a female dog/a curse word.
Using bitch in a harsh way is profanity. Using it intelligently gives it a new meaning. As does kid.
So, just use them in their terms of definition.