SSL Labs is a tool mainly used by the website owners/administrators, not so much by end users (and if at all an end user will then complain to the owner about a

SSL Labs is a tool mainly used by the website owners/administrators, not so much by end users (and if at all an end user will then complain to the owner about a low rating). Downgrading the rating because he used a "fishy" CA might motivate the website owner to switch to a CA with better standing. The bad CA will feel pressure to clear their standing.