I wonder, too. I've gotten into the habit of eating a LOT of garlic!!! A little raw and a lot cooked.
Here's an article saying there was a study showing it is good for the brain, contrary to the claims you are referring to.
Andreas Moritz, "Amazing Liver Flush" guy, says Aruveydic and other ancient systems say "NO garlic." Haven't checked that out yet.
There are so many studies showing garlic lowers cancer rates and kills cancer cells... but the argument against says it kills good bacteria and healthy cells...
Would sure like to see some more on both sides of this!