Ah, I interpreted that as persistent jet washing will kill any bearings. They do claim to use labyrinth seals, but perhaps they're of a lower quality than the CX75s.
SLX FH-M7000 weighs about the same as RS505, but has Labyrinth & Contact seals. The flanges are further apart and you'd have to use an MTB cassette if you want 11speed.
You interpreted that correctly, unless the plan is to rebuild them with new grease after every wash, in which case have at it.