Why? Why if an altcoin steals an idea does that make it not worthy for bitcoin? By that logic, bitcoin isn't even worthy enough to be bitcoin because there are dozens of fake fork coins which employ the exact same mechanisms. P2PKH isn't unique, PoW isn't unique, secp256k1 isn't unique, 10 minite blocks aren't unique, I could go on all day.

And then, why does it even matter? Who cares if 100 altcoins also decide to implement Lightning? All that means is that it has merit and people want to copy it.

What do suggest instead? That the devs patent Lightning?