Why did the ETC classic hard fork create a new coin but these recent forks don't?

Is this understanding correct: Really, they all make a new coin, it just happens to be that everyone switched over so those old coins don't mean anything, while by ETC, they cared enough to legitimize the coin? If this is the case, why don't I need to do anything with my ETH during a hard fork? Wouldn't I need to transfer it to the new chain like in the ETC example?

Edit: I understand why ETH/ETC forked, I want to know how that specific fork resulted in a new coin