While we cannot make this decision on behalf of a theoretical future Bitcoin community, I think burning vulnerable bitcoin is inevitable.

First of all, I think it’s the right decision. In a world where a CRQC (cryptographically relevant quantum computer) is on the short-term horizon, these coins will not remain with their original owners. No amount of hopium will solve that. Instead your options are only (a) freeze or (b) let some CRQC owner eventually steal them. I definitely prefer (a).

Luckily, it doesn’t have to be a lot of coins - any addresses which were created from a standard seed phrase + HD derivation can be recovered with a QC-safe ZK proof. It’s only the very very old coins (or more esoteric wallets) that would be frozen.

Finally, it’s worth pointing out that I think this is inevitable. In a theoretical future where a CRQC is on the horizon, both forks will exist. The market will ultimately decide which bitcoin they value more - one with an extra million coins of supply as the CRQC owners steal lost coins or the one without. I cannot imagine the market preferring the former.