If we're just talking archival and my goal isn't to increase access and availability to those books, then I'd also consider the availability of the book generally outside of my collection. My institution may not personally need to preserve some major holy books, new popular novels, classics, books still in print, because other institutions, people, and culture overall are doing that preservation work for us. I would focus instead on things that are more at risk (e.g.less popular but still important.)
With a watchful eye of course to notice when a book is losing popularity and needs an additional hand to preserve properly.
I'm not a librarian though and defer to them as experts here. They're much better at this than anyone else.
Outside of the thought experiment, banning books is different than choosing to not preserve them or keep them in a collection.
Removing a book that would otherwise fit the criteria of preservation just because it covers a "politicized" topic is different than a book becoming low value, getting superseded by newer editions, or no longer being worth preserving by that particular institution.