The spirit of the regulation is to make sure it is not emitting ozone like this ozone filter-less purifier: GreenTech GT-50.
It may be "painless" but if it costs $X per unit to certify and they make $x-.01 per unit, the company isn't going to sell that in CA.
The harm caused by the lack of a super cheap and effective air filter, especially in CA where we can get smoked out for weeks due to fires could be greater than the harm reduced by the regulation. Especially when it is obvious that this in now way could emit ozone since it is just a fan and a filter.