France specifically lists political affiliation among protected categories, while post-socialist countries flat out prohibit hiring decisions on anything unrelated to the ability to perform the job (and arguing “cultural fit” qualifies would be a difficult proposition, were the rejected hire to actually go to court).

Governments may be allowed to be more discriminatory for national security reasons, and AFAICT security clearances are in part a backdoor to get this to be permissible in private employment as well.

(Of course, it’s a different story if the political organization in question is actually banned, but in most civilized places that’s a very high bar—I’d argue that’s one of the qualifications of the moniker, even.)

Not to forget: Government is also a large employer, not just the private sector.