The reason is simple -- a virus that kills its host doesn't survive to replicate as well as a virus that keeps its host alive to spread the virus further. Successful viruses don't kill. Those that kill a high percentage of hosts tend to not spread far, they burn themselves out. See Ebola.
So -- More rapid spread does not make it more deadly, it only means more people get it per unit time.
I wish headline writers weren't such idiots. I know, lotsa luck with that, Bucko.
How many people will be hiding in their homes peeking out the window with masks on this time? A few morons at least