APY The start of your last post is spot on up until here:
“but you can not say “the food that person certifies is not kosher”. The more private an individual the better chance they have at a successful defamation suit.”
This part contradicts your first few lines
In order for the court to determine whether the defendant’s saying “the food that person certifies is not kosher” is defamation or not the court would – by definition- have to get involved “in determining if the shulchan aruch and nosei keilim or lihavdil the jts handbook on kashrus is what determines kosher.” Which as you correctly start out saying, they will not do. There is zero chance of a successful defamation lawsuit much as if you sue me for saying your Eruv, or Mikvah arent kosher