I would not choose these strong words, Eddy, people believe in many things.
Otherwise, the statement is really wrong, of course - in today's world, the new stuff spreads very quickly, so it's certainly not needed to "cooperate" with malware authors. Besides, more and more malware authors are doing it for profit - so sending their stuff to AV companies wouldn't have any sense for them. Last, the source code is not needed to add the detection of the particular malware.
However, some virus writers actually did (do?) that occasionally - but that concerns rare zoo stuff (proof of contept malware, possibly even intentionally disabled to avoid spreading), not "new threads". But again, this has nothing to do with the detection of AV programs.