there are multiple aspects of defamation you may have forgot about don. one is malice, one can easily connect peoples actions towards patrick after the ******* of a well liked member. people went off the edge and began calling him out on his nonprofit status as well as "maliciously" flagging his posts on CL.
that added to the posting/questioning of his nonprofit status dives into a portion of defamation called "false light" which means the information posted may not be false, but is definitely misleading and causes harm to the sellers reputation. that is a component of defamation. there is an emotional aspect to this which is weighed on also. he may or may not have mental health issues, but if he does and has had more visits to the doc over the last few weeks due to this it also casts a shadow onto your ridicule of his business...whether you are telling a lie or not.
it is a tricky subject and i have become involved highly with defamation because of a suit i have against a neighbor who defamed my name when i began working for city council almost 2 years ago. my neighbor lost to my boss and the issues began from there. i am looking at 1.5 years of this issue and still no end in sight.