My attempt at a legitimate argument: Perhaps they are an attempt to put government-wide "pause" on public communications from all agencies, so they can a) reduce the odds of these agencies making statements that are directly counter to the new government's strategies, and b) buy time to put those new strategies into place (confirmation hearings, realignments, etc). In other words, never intended to be permanent gag orders, more just in the name of implementing new message discipline.

As for your second point, I think much of this has to do with how the language of power is different than the language of truth. The Republicans in the USA have historically bought more into the language of power than the Democrats have. By that I mean, given the choice between clearly and honestly explaining your position, and instead communicating something different that you believe will better advance your agenda, the Republicans have generally seemed to be more in the second category than the Democrats.

This shouldn't be a politically controversial point. The latter style language is more common in business, negotiations, diplomacy, etc. Democrats can do it too, but it's less of a campaign style for them.

It's also not a secret, which is why it feels easy for Republican supporters to defend. To them, it's not ridiculous that the Republicans never came up with an alternative ACA plan during Obama's presidency. There was a very clear calculation that "opposition only" would be more effective than coming up with a plan replacement. And it's obvious, too, because as soon as you suggest an alternative, you open yourself up to attack. Meanwhile, the Democrats regularly mocked them for having no better alternative. For some of them, this might have been just a communications strategy, but for many others, they were actually upset and mystified that the Republicans were not advocating an alternative plan.

So, these "decisions that are objectively wrong", it's just because it's worth it to them. Be anti-science because it increases your odds of gaining power. Supporters agree, and generally believe that all that stuff (science, reality, etc) will be dealt with after they gain power. They're very trusting that the people they support are more competent than they are letting on, and that it will work itself out.