Imagine you go to a hotel and see an USB A port on the wall and you try to charge your phone, then your phone starts to smoke or simply ignites. You find later that port was not a standard USB A port, but a 220 volt plug for something custom. Should the hotel be responsible for that? I think it should. If it looks like a duck ...
Their website says that it uses USB-C for charging and the charging port accepts stock USB-C cables, it's not even remotely reasonable to bury within the warranty a statement which says "oh, by the way the device cannot accept USB-C cables -- if you use a made-to-spec cable that fits in the port, no warranty for you!".
If you shove 9V into a 5V device, bad things will happen, regardless of Nintendo is anti-standard or not
They put USB-C on the box. They screwed up the design. They should be forced to have a recall, or extend the warranty.
Nintendo should have taken more steps with their charger to restrict the Switch to authorized chargers only, rather than permitting unsupported chargers (such as standard USB-C ones) from being able to power it. Or even just outright used a proprietary connector!
None of this is any fault of the chargers. They’re the ones adhering to the standards correctly. The Switch is at fault.