I'm not shifting any goalposts. The Romans did drive the Celts to extinction, which is why their language disappeared. I already clarified I don't mean the Romans literally killed every single Celt, but their mass killing coupled with repression obliterated their culture, something you keep ignoring and are not addressing, just repeating over and over that the Romans didn't commit genocide on them.
*sigh*
The Romans occupied Britain and did not drive them to extinction.
The Romans did not wipe out the Gauls when Gaul was occupied.
The reasons that Latin replaced Gaulish was not because all the Gauls were killed.
Latin replaced Gaulish due to prestige, similarity of language, and administrative dominance.
Yes, administrative dominance will have involved suppression of rebels but Gauls that accepted Roman rule (ie not rebels) were not targeted with suppression/oppression/repression or extinction.
You are claiming that any Celt under Roman rule was killed if they spoke their native tongue, that they were deliberately targeted because of that. That is inaccurate.