I would be extremely surprised if they are not making sure the snakes are getting enough to eat. The study would be useless if the results come back that the snakes starved to death. They want to find out what the temperatures do to them.
Unfortunately, I don't see any other way to test if they can survive the cold temps than to expose them to the cold temps. And to conclude "they can't survive", they will have to have fatalities.
And while you are correct that doing this to snakes will cause less of an uproar than a similar experiment done on something fluffy, don't fool yourself into thinking that these kinds of experiments aren't done all the time, even to fluffy animals.
I am sad for these 7 snakes. But I'd much rather have these 7 snakes slowly die of exposure to the cold winter than to have our entire hobby slowly (or not so slowly) die of exposure to negative press based off of totally false "scientific" reports.