My understanding is that all public launches are supposed to be closed. I heard some areas are still open but if you go to the link I provided, the site as a letter sent to OFAH by the province indicating all launches are to be closed.
I'm in Oakville, and the public launches are closed, as well as I have a boat access only cottage close to Kilbear and the Parry Sound public launches are closed, the Carling Township public launches are closed and the marinas aren't supposed to let you use their launches unless you can prove that you provide an emergency service or are accessing your primary residence.