I don't think anybody is saying that no steps should be taken to contain and mitigate. The question is what should those steps be.
Given what we know about the virus and that there's no vaccine for it, it would seem logical that we take steps that go a little above and beyond what we do for seasonal flu. Stuff like more telework, limiting travel, etc. This wouldn't mean hoarding toilet paper, banning gatherings, bringing in the National Guard in certain situations, etc. You can take this seriously, more seriously than seasonal flu, yet not become hysterical.