actually its more like you saying. that altnets are bitcoin because they too use p2wpkh. if you want to get pedantic.

a transaction that includes a utxo on the blockchain thats using say p2pkh that gets confirmed by the bitcoin blockchain. and accepted by fullnode peers of the bitcoin network. are part of bitcoin.

if 'payments' use p2wpkh but are denominated in 'picobitcoin-1' (millisats) which bitcoins blockchain rules dont understand and wont get confirmed by the bitcoin network or accepted by bitcoin full node peers.. then its not bitcoin.

maybe you need to learn the differences of what LN does vs bitcoin.

..
i find it strange how the altnet lovers are trying soo hard to declare their altnet as being bitcoin. even when its a separate network and different payment 'forwarding' system to bitcoin.

if they just said that its a multicoin faster payment rail. and listed the pro's and cons honestly. they could actually find a niche and their own community of loyalist that want such things. without trying to tarnish bitcoins utility and over exaggerate the altnets ability. just to promote their altnet as being better than bitcoin.

the funnier thing is these altnet lovers also want to now express that bitcoin full nodes dont need to be blockchain archivers to support the backbone of the network, where they want to promote that 'fullnodes' just need to scan the blockchain once and just keep a UTXO set to ensure the users own funds are legit.

in my eyes thats just too much BSing to try getting others to stop supporting bitcoin, while risking their value on altnets