It is layer 2.  It's layer 2 on BTC, it's layer 2 on LTC and it's layer 2 on any of the other chains that support it.  Being layer 2 on other chains doesn't cause it to stop being layer 2 on BTC. 

It operates on top of Bitcoin, ergo it's a layer.  To date, you are the only person I've witnessed on this forum who is utterly incapable of comprehending such a simple concept.

Whether it's unique to one blockchain is irrelevant.  If I'm using LN to send and receive BTC and BTC alone, it literally does not matter what's happening on other blockchains.  And even if I were using LN on other chains, that still wouldn't detract from the utility of LN on BTC's chain.

Stop acting as though you're making some sort of point.  You're just making noise.