This isn't true. The appeal of conservative leaders and opinions was not increased. The opposite is what happened.
Am I missing something?
Jost is Liberal, which does change the peer review standards, but I think his point there was that overall, in those named countries, Conservative/groupism tendencies increased, so on the whole, threat and uncertainty increases Conservatism. The groupism might have even had a hand in setting the stage for WWII.
Unique attributes can bend the rules, (for example, if there are hundreds of Liberals and one Conservative, they may try to gang up on the Conservative, to redistirbute his stuff), but in most cases, Libs will go to ground, and avoid confrontation (or people genuinely become more Conservative - I’m not sure which myself), as people look for allies.