I’m also a physicist and (also?) a leftist and I don’t think Motl is particularly wrong in your quote. Exaggerated, but I do think the Nobel prizes have a leftist/progressist tendency, and his examples are not that far off.
So in the context of this years prize, I think it’s fair criticism, albeit somewhat carelessly delivered and unrigorous.
There's a neoliberal bias where the peace prize is given out to Kissenger, Obama, Arafat/Perez/Rabin.
But if you only gave it out to actually peaceful people there would probably be a massive leftist/progressive slant (which makes no sense to the people in the crowd who think the CCP is leftist, but that is their problem).
So in the context of this years prize, I think it’s fair criticism, albeit somewhat carelessly delivered and unrigorous.