There is actually some real disagreement over some of these measures. I think it causes more problems to pretend that isn't true, because it makes people think something funny is going on, when it's really quite natural.
Part of the reason is because political leaders want to be able to get out of the hot seat, and if they say their decisions are just reflecting the science, they can avoid responsibility. But public health decisions are never just about science, they are always in large part about understanding behaviour and balancing competing interests. Those are easy things to get wrong and no one who will have to take responsibility in the polls wants to be on the hook.
The public also has some blame - they are unwilling to hear that perhaps only so much can be done, or maybe in some cases nothing.
So it would be much better IMO if they were open about the pros and cons, and unknowns, of different options, rather than making out like people who question certain things must be idiots.
But in general I think people see authorities making decisions that seem illogical, or contradictory, or seeming to take advantage of circumstances, and it makes them think there might be an agenda. Or they hear the rhetoric going around in public and worry what it means. For example, many people are now saying things about protecting the vulnerable that would not have been accepted before with regard to, say, flu. Even though it seems like it would equally apply. Or they see serious restrictions to travel and wonder, how easy it is to supress basic rights in a democracy.
I am outside the UK, and my regional government has not been sitting for months. They are meant to go back into session after Christmas and we have been told they will request to prorogue the house. It could be a year without sitting - and yet there has been very little pushback in the media. It makes people question motives.
In general though,