Yeah, it's a shame... I know GM was just covering their butt, but it'd nice to trust your customer a bit more.
Every EV manufacturer is a bit paranoid about charging from existing outlets in their customers homes . . . . and for good reason
When a Tesla catches fire (a VERY rare event) you would think it's the only vehicle fire in the country that day, when in actuality, dozens and sometimes hundreds of ICE vehicles burn every day, but EV's are new technology, not well understood by the general public, so every overly publicized instance is a black eye on the whole industry and every manufacturer is doing all they can to make sure those don't happen
Some houses still have ancient knob and tube wiring which may not be safe for even a continuous 10 amp draw, so many EV's came with the 8 amp home use 120 volt EVSE's. Our 2012 Mitsubishi's came with a Panasonic EVSE which did 8 amps and ONLY 8 amps - Mitsubishi rightly knew that all that was needed to seriously damage the perception that EV's are safe, dependable vehicles was for
one person to burn down their garage or house charging their car, so they cautiously went with a very safe 8 amp EVSE which couldn't do any more than that - One of the most popular mods was to send off your EVSE to a company and have it modified for 12 amps
You will notice that when they advertise recharge times, they always give a figure for 120 volts (plugging into an existing outlet) and then a much better sounding number for 240 volts - They don't supply a 240 volt EVSE and they assume that you will have a professional install one when you buy it, because most folks don't have 240 volts available in their garages
Thankfully, instances of EV's burning down houses or garages is very, very rare and that's largely due to the safeguards the manufacturers built into the charging process
Don