In the UK, for example 10 million EVs all pulling 7kw would overwhelm the roughly 70GW potential of the grid. Even a million EVs charging at an inconvenient time could add a 7GW draw which is enough cause a problem.

It creates a wifi access point in your garage that you cannot turn off:

  TeslaWallConnector_<unique-id>

I would love to be able to hack any firmware to disable that.

I also read that a connected tesla car can force an over-the-air firmware update maybe through the charging cable or wifi, but I haven't verified that.

An owner voluntarily downgrading firmware to gain control of your hardware IS NOT A HACK.

And if an adversary is doing this, then they have already breached yoir physical security.