The virus cannot be stopped without shutting down the economy.
Shutting down the economy has a price. (And, as an aside, the Left would be screaming about Trump being Hitler.)
At an individual level, I try to protect myself and my family. But, I'm not willing to quit my job.
At a societal level, I also don't think we should shut down the economy to maybe stop the virus. We should work our way through this, fighting the pandemic as we go, know that there will be casualties, and that is not desired, but a sadness that must be endured for the good of all.
You can always stop all casualties in a war. All you have to do is surrender. But, surrendering has it's own cost. The question at a societal level is this: Is it worth it to save the lives? The same is true for this pandemic.
----
To directly answer your question: I think both warrant a response.
The federal authorities clearly have the power and jurisdiction to protect federal buildings from rioters, and doing so does not suddenly make US Marshals "nazi storm troopers." That is easily done; it is a no brainer, and the only reason to question that is for political reasons.
As to the pandemic, the state authorities clearly have the power and jurisdiction to handle things. The feds can help. Maybe we should change our system of government to give more power to the president, but I'm not sure that would be a good idea in the long run, especially with one side of the country electing dictators all the time, amiright?