In this case, I think they are not completely unreasonable. This specific move is one of the things the executive branch has been allowed to do, by previous legislators who gave it this power.
Yeah, there's quite a lot of reason to believe SCOTUS is political. I think the simplest one: the conservative justices lied and/or told half-truths about their views on Roe v Wade. Under oath. The ones who lied are liars. The ones who dodged the question are politicians.
It's also worth pointing out that there is a gulf of difference between how a court interprets law and the constitution, and how a court interprets a previous "Precedent". Courts have a lot of power to throw out or reverse previous precedent, but much less permanent power to change interpretation of the laws themselves.
> Courts have a lot of power to throw out or reverse previous precedent
Yes, we've seen the death of stare decisis.
> less permanent power to change interpretation of the laws themselves.
They have to work harder to do it but this court has not been shy about reinterpeting everything through the Calvinball (originalism) lens.