I see no circumstance under which I would ever support asking for a halt in trading on a centralized exchange. Trading on the exchange is trading book entry claims on the exchange's wallet. Even in the extreme case of a rollback or other problem affecting wallets, traders can assess the impact that might have on the solvency of an exchange and trade accordingly. However, an exchange might on its own (or in discussion with other exchanges) decide to halt trading. That's their call, it is their platform after all.

If there were a problem with the blockchain affecting (or even possibly affecting) wallets, I would support asking for (and recommending) a halt to deposits/withdrawals until it was resolved.

During the initial stages of the 202612 attack exchanges may have stopped trading as we put out an general "red alert" until we actually figured out what was going on. Most decided to restart it but they kept wallet transactions on hold until bug was identified and the vulnerability deemed over.

With respect to the DAO, it wasn't even a bug in the coin at all. Ethereum devs acting in that capacity shouldn't have been involved nor should they have asked exchanges to do anything in my opinion, nor should any fork, hard or soft, be on the table at all. My other (perhaps more controversial) opinion on the matter is here: https://bitcointalk.org/index.php?topic=1516067.0

Needless to say I will never support a fork or rollback or any other sort of meddling with coin ownership in Monero on the basis of an external incident that was not a flaw in the implementation of the coin itself (an example of the latter being the overflow bug in Bitcoin).