How about those who feed their dogs raw meat? Have you tried putting raw and
cooked side by side and see if there is any preference at all, or is there
really absolutely no preference? Dog preference wouldn't guarantee human
preference, of course, but it would be a less biased test than relying
solely on the claims of biased human beings.

If there really is no preference, as some have said, even that argues
against the idea that taste preference was the main reason behind the
adoption of cooking by human beings. Because if taste is the main factor, to
make such a significant change of adopting mostly cooked meats over raw
meats there would need to be a taste PREFERENCE, not just an equal acceptance. 

If there are opioids in cooked meats and the opioids really do trigger
addiction, one would expect a dog or a human to again prefer cooked meats
and one would expect that preference to increase as dependence on the
opioids increased.