The lockdown policies inevitable have political component, because they are made by politicians and will be evaluated in a political framework. And for a politician it is always practical to err on the CYA side - one extra day of lockdown costs the politician very little, as the costs of it are not born by them personally and are largely very hard to quantify, they are distributed among the population and spread among many consequences, small and large. However, if the politician raises the lockdown prematurely, the blame - in a very quantifiable and ready-for-election-ad form of raising case numbers - would be directed personally at the politician. If the political power of those who suffer from the lockdown is not large enough and organized enough to exert significant pressure, the smart politician would extend the lockdown until there's no conceivable risk to be blamed if anything happens. Virus research, vaccine research, etc., is science, but decisions on what to do with it is always political. And thus those who want to influence it obviously make a political action.
With the current protest, the political situation changes. Opposing these protests is a political suicide. If you can't oppose them, the only way is to have some contrived argument where you are for lockdowns (because see above) but also for protests.
> health officials should not have their risk assessments swayed by political considerations.
You can publish raw information about risk - which is complex and uncertain, and step back, but then you will have little influence on political decisions that follow it. Or you can recommend a policy - and by that inevitably contaminate the scientific assessment with political stance and become invested in certain policy. I'd much like the former, but vast majority of the policy in the US lately completely rejects the idea that the population can be trusted with full information and making its own decisions about it.
The ruling paradigm is that the government should limit people's choices for their own good, and push them into actions that it thinks are beneficial for them. And most people expect that from politicians and blame those politicians which didn't limit their choices enough and allowed them to make choices which ultimately brought bad consequences. So, the politicians and people that want the political action to happen play the game that the public wants to be played.