Sadly because many of the politicians on the so-called right at present are unlikely to have their power limited by fully justified accusations of sexism, racism etc. Other smears may work there but not those ones, it would seem. [1]

And that's great, stupid smears are ineffective! What is not so good is solid evidence of serious racism and misogyny is also ineffective.

Historically there have been plenty of politicians closer to the so-called right who would have the power diminished by being foul. There may well be still in certain areas.

What would be nice is if A good take a little of the good sense from B and B a little of the good sense from A.

What we have isn't that, whatever labels you put on various "sides".

[1] "Jewish space laser" for example. That may not be a smear.