Bitcoin isn't fungible anyway.
Yet Segwit drives a trifurcating wedge right through
any vestige of fungibility. Three distinct classes of BTC. All with differing security properties. This is novel in Segwit.
And I think he was referring to the fact that LN pretty much required segwit.
Well, for some value of 'pretty much' ... (i.e., No, a malleability fix is
not required, it merely makes it easier. And Segwit is not the only possible malleability fix. Even if it were, The SegWit Omnibus Changeset bundled a bunch of other crap in with Segwit itself. Lastly, the security-destroying so-called 'soft fork' activation methodology was not required).
... well, for
this particular implementation of LN, anyhoo.