What's special about EVs that gives them this loophole? Is it something to do with not having dealerships and going direct to consumer?

Emissions. Most things about ICE cars come through EPA and CARB.

I'm pretty sure that the only diagnostic codes that an ECU is required to output are emissions-related codes. Since EVs have no emissions, I'm gonna guess they can force all diagnostics through the dealer if they really want to.

without oil change and wear of brakes there is little need for inspections.

Ball-joints and tires are still consumables, and they go faster as weight goes up.

Surely wheel bearings too. And you have to do a safety every year to check for rust perforation (at least in the U.S. states that still do that).