As a classic car owner with a (small) 1300cc engine who drives their car about 5 times a year I would apply the same argument :-) though maybe it'll be banned now because my car isn't as quiet as a sewing machine...
Different kinds of emissions. CO2-wise, yes indeed the moped is less harmful.
But the other emissions... a modern car is essentially a chemical lab on wheels. At least one actively managed catalytic converter to remove NOx, another one for diesel engines to burn leftover carbon monoxide, and then a particulate matter filter to trap and burn-off soot and other micro particles.
A two-stroke engine usually only has a passive catalytic converter and that's it. It emits by design unburned fuel-oil mixture into the exhaust because the mixture is used as a lubricant, and beyond a muffler it has absolutely zero noise emission control.
It will never fly because the demographics that are usually supportive of that kind of legislative action are almost exactly the same demographics who buy 3-row SUVs for 2-kid households and hand wring like it's the end of the world if you put four adults in a compact car or throw plywood on a roof (but a kayak is fine).
2-strokes have remarkable power-to-weight ratios and are pleasingly mechanically simple, but goodness me they're dirty.