"Here’s a P.S.A. for the copycat entrepreneurs with no shame in their game. You will never succeed."

Except for all the successful business owners who claim to have done exactly that and done way better than those they copied.

This is yet another person trying to stifle competition by claiming it's unethical.

Why is it unethical for multiple companies to provide the same service or product?

It's not. It is, however, unethical to call for a boycott simply because it'll make your business more profitable.