They are wrong. The Switch console itself is USB-C standard compliant. The dock has a slightly smaller plug to make it easier to dock / undock the console. 3rd parties try to replicate the smaller plug but don't get the tolerances right causing a miswiring.
I can’t charge my phone with the Nintendo Switch charger, it switches on and off repeatedly and doesn't charge. And my other USB-C chargers don't negotiate the power needed with the Switch so it charges very slowly if you don't use the included charger.
I charge the Switch console just fine with a PD USB-C charger. PD is very negotiable and the Switch only supports a few voltages so your charger must support the same voltages.
As far as I understand it (correct me if I'm wrong), every proper charger is supposed to support the exact same list of power combinations from 0 up to whatever its max wattage is.
The switch dock demands 39 watts, which implies 15 volts, but the switch itself will negotiate any voltage when standalone.
The only time things break is when you attach a broken charger that outputs 9 volts onto a wire that's supposed to be doing 2 volt signals.