When you no longer hold you don't suddenly stop having an insight into the Company, particularly when you were a holder for a significant amount of time.
There are many non holders here (some who were once holders) who continue to put their two cents in, much of it worthwhile imo. You may not like the message cfp espouses however he does have a right to an opinion surely .... otherwise maybe you ought to only be sharing 30% of your thoughts considering you have offloaded 70% of your holding