If the miners supported BIP148 and they were actually principled enough, they would switch to a pool which supports BIP148 or allows them the option of mining on that chain.

Individual miners will act based on their own economic incentives - pools will act based on their broader/long-term economic incentive.

If pools believe that they have no broader economic incentive to support a specific solution, that's the only situation in which they'll be neutral.  This applies to other pools, including SegWit supporting pools, not just AntPool.