Problem is firefox has no control how they do their certificates and if must match registered one online if not they must redo their certificates. Also on the privacy settings if you look there - there is a option to auto select as well. So did you do that yet?

Don't matter for me how they do it. Even don't matter for me if its valid or not. Just want open these pages quickly and not garbage my browser with these exception. May be there exist some root certificate that I can import and all of these self signed (fake, not valid, etc.) not displayed these warnings? May be there is option to turn check for certificate completely?