That's FUD and a bit of a straw man. No one is debating whether or not you should be able to personally tinker with your car (electric or otherwise) because that's going to be possible regardless of compatibility of parts. You're perfectly welcome to go attempt to to swap your engine and fail horribly right now on your 20 year old gas guzzler or 20 years from now on your high tech electric car. That's not a reason to keep parts from being interchangeable across cars/manufacturers.