Sometimes issues turn into something akin to a college football game, when the reality is more nuanced.
This isn't a question of separator vs no separator. No one needs to lubricate the belly skin. The issue is crankcase return vs none.
It is entirely possible to create a harmful separator installation, i.e. one which returns liquid water to the crankcase. Simply cool the system, condensing water and fuel vapor to liquid. The separator will capture liquids, as intended. It doesn't care what kind of liquid.
It's also quite possible to install a system which maintains gas temperature above the dew point of water and fuel. The only liquid will be oil.
Inability to maintain separator temperature above dew point does not mean a separator is ill advised. However, it does preclude a sump return.