Why? Are you retired? Because if you aren't, if you're working and putting money into a retirement plan, you are much better off with a bear market, especially one like this that is practically guaranteed not to run for years. When you're a buyer you want prices to be low.
This assumes a return to trend, right? If stocks are temporarily depressed you can get them at a discount.
If stock prices are permanently lower as a result, though, it's certainly not good for you. And, believe it or not, this is probably the more accepted idea -- that price movements are memoryless, that we shouldn't subscribe to the gamblers fallacy (that down today means up tomorrow), and that being happy for a price drop is a form of timing the market, which is frowned upon.
I don't fully buy it, but it's worth thinking about.
The only way that can happen is if the economy is permanently less productive. There are things that can make that happen (climate change, for example) but the corona virus is not among them. Fear of the virus is causing vastly more damage than the virus itself. The virus itself is mainly killing old, unproductive people. I don't want to minimize the severity of the problem or the emotional pain of people who have lost loved ones, but in terms of long-term economic impact the corona virus is really not a problem.
A short-term reduction in profits reduces the discounted sum of future returns. Not as much as if interest rates were lower, though.
Also, the example of the virus could indicate that these infections are on average more common and more severe than we figured, and that could reduce expected long-term growth.
Finally, a "pause" on activity could delay productivity increases. Probably a small effect, but this could represent investment not happening in the short term.
I sent some lumpy buy orders yesterday, but I'm not sure I was right to.
This is the reason why more than a 10% drop or so (assuming this doesn't chain-cause a recession) isn't justified. That doesn't mean stock prices aren't permanently lower.