They don't care. It's the same shit about how we "only show up right before elections and disappear afterward," even though we're saying the same things all year every year.

At a certain point it's just a symbolic belief, you say leftists are bots to signal you're in the in group, you say Trump is "Putin's puppet" for the same reason. Even if it were incontrovertibly proven wrong, they'd either keep saying it anyway or just find another way to signal to the in-group. You can find similar behavior in Red MAGA. Whether they believe it vs using it as a slogan or rhetorical device is unclear, and in fact it's unclear if they have any coherent beliefs underneath the sloganeering at all.