yes I agree it does not matter how it’s propelled without peddling or what you call it throttle , push button , twist switch otherwise disabled scooters would be illegal as they do not have pedals and cand be propelled by a motor and battery.A EAPC can't be illegal if the thumb push/ start control can't propel the bike from a standing start , the law states it must be propelled by pedalling.
Nearly all EAPC's have 6kmh walk assist that doesn't require pedalling.
The law states that a EAPC must be propelled by pedalling .
so the only issue is the speed one can go under power without peddling.
Or as Sanegal pointed out a throttle is for an internal combustion engine