Why would anyone need to compete with Bitcoin on it's own chain if their coin is better?
You're welcome to question why anyone would need to compete with Core on the current chain, but it's not my place to answer. Some people want to and they're entirely free to do so.
It is your place to answer, you're the person I asked.
Then I apologise for my lack of psychic powers, because I can't guarantee a correct answer. The obvious response would be that the people releasing competing protocols are dissatisfied with the product as it currently stands and feel they have the superior code. You tend to proclaim, however, that the intent is hostile and it's simply a power grab. Personally, I don't buy that, because again, you can't seize control when there's no one in control to seize it from. The miners and node operators are ultimately responsible for securing the network.
And people are, of course, entirely free to do all sorts of foolish things. Free choices are not necessarily good choices.
Huzzah! So we're in agreement that alternative clients have the right to exist and are free to compete on the current chain, even if you don't personally agree with what they represent. I withdraw my previous accusation, then, you're not a protectionist apologist like the OP.