The heat decarboxylates the THCA (tetrahydrocanabinoic acid) and isomerizes the CBN/CBD (canabinol/canabidiol) to THC. The ideal temperature is somewhat like 105 C. It is why some people says the weed must be "activated" by heat to be effective. Simmering the weed in boiling water does it. And heating it by any another means too, more or less effectively. So, as microwaving the weed will heat it at +-100C, it must work (at least in theory)
And you are right in questioning, cause is the better way to learn