EVs have heavier batteries and ICEs have heavier engines and drivetrains. Go compare two similar models at most brands and the curb weight will be within 50-100kg. Add in a full tank of gas to the ICE and the will likely weigh about the same.
I guess it's increased/comparable weight + lack of gas tax. There's definitely something thrown off by EVs and the suggestion to tax charging EVs specifically makes sense.
