My guess is that being self employed they need to keep working to get some income. I'm self employed (driving instructor) and have been told not to work, but there does not yet seem to be a way to get some of the income replacement stuff the government has been talking about just yet. (Very very happy to hear from anyone who can put me on the right track !)
If I was employed I'd be getting paid. Ditto if sick with the virus. There is an 80% up to £2400 per month for workers scheme either already, or on the way. For the self employed, currently zip.
At least I'm allowed out for exercise, so I'll be taking long walks every day. Glad I live in a tiny town with easy access to hills and countryside!
Rug
Edit - I think Anti's quote in my sig is very true just now. Hope you're OK Anti !