LOL read the code. learn it
native keys will still quadratic spam.. all segwit does is disarm the segwit priv/pubkey users that voluntarily move their funds to segwit keys from being able to quadratic/malleate.. but doesnt disarm the native key users.
segwit doesnt disarm the network. meaning soft or hard consensus or bilateral. segwit will never be able to achieve the quadratic/malleation fix promise

they cant even just switch off native key utility after activation either because there are millions of unspent outputs based on native keys and for segwit to even work would need to allow those native unspents to be spent.

segwits 'malicious bloat/doublespend fix' - empty gesture that wont work (requires 100% funds on segwit keys and only transacting to other segwit keys)
segwits '2.1mb boost' - empty gesture that get to that expectation (requires 100% funds on segwit keys and only transacting to other segwit keys)

all segwits ability does is move blockstream to being the centralised "upstream filters"