It never was.
Flu virus has a 6ft spray radius - some studies have shown Wuhan flu might be 12. That’s NO reason to not allow walking the dog.
There’s some studies that say this virus is aerosolized but the WHO and CDC have denied that’s the case. Even if it was - walking the dog is still not a threat because the virus will be severely diluted in the air!
It’s getting to be summer in the southern hemisphere, and sunlight kills virus quickly. There is NO reason not to let people be outside.