Some opinion, aimed at no person in particular....
I think these days it seems that people are basically taking the bees' honey stores away and replacing it with sugar water or corn syrup. Not leaving the bees enough of their own honey to survive the winter on, thus begins a nutritionally poor diet for them to get by on. Bees are terrific at finding flowers within miles all around of them, and if there is nectar to be had, the bees can build comb amazingly quickly in the Spring. Bees with access to nectar will build comb as fast as they need to, to keep up with their hive growth. They won't build comb according to what WE decide they need. We eliminate the variety of wildflowers that they could survive on during all seasons, and we force bees to do things according to our own schedule instead of working with bees' natural seasons. We don't let them do what they need to do or have what they need to have to be strong and healthy. You can feed all the sugar syrup in the world but it still won't make bees build a lot of new comb in the Fall. Not saying anyone here does this, but if you take most of the bees' natural food away and force them to survive/starve on sugar water or corn syrup for a year or two, it doesn't surprise me one bit when they succumb to various diseases, toxins, and parasites.
Sorry, don't mean to sound like a 'tree hugger'...but hey!