I keep hearing BIP110 proponents describe their fork as being the safe option even with a minority of hashrate due to the "asymmetry" that the BIP110 chain can wipe out the legacy chain, but the legacy chain cannot wipe out the BIP110 chain.

This asymmetry is real for ANY soft fork, but it doesn't make a minority hashrate soft fork safe.

Softfork nodes reject legacy blocks, so they'll never reorg onto the legacy chain

Legacy nodes accept softfork blocks so they will reorg onto the softfork chain if it has more cumulative work.

Once again, If it has more cumulative work.

Nodes (including miner nodes) follow the most-work (valid) chain. A minority hashrate softfork chain accumulates work slower than the legacy chain.

With a minority of hashrate the BIP110 chain will not persist as the most-work chain, it will fall further and further behind over time.

The BIP110 chain could get lucky and get ahead temporarily, but over time the luck will run out and once it falls sufficiently far behind it won't ever catch up to the chain tip.