There was no tax! People switched to cars simply because they wanted to, not because they were forced to. Whereas there is a tax levied on ICEs in many places.
"Examples from a number of countries show that this uptake can be enhanced by well-designed incentives and taxes."
"most European countries have based their vehicle taxation schemes on type-approval CO2 emission values and increased the number of incentives to purchase new electric vehicles."
To me it seems that ICE owners are taxed more compared to EV owners. I don't understand what exactly it is you argue against.
edit: also, nobody taxed horse owners extra just to clear the way for cars.