It's probably a government request. But let's give them benefit of doubt. My guess is that there's a business reason behind it. Probably they want to track you.
I really doubt they care about tracking you that much. Tor is so infrequently used that it's not worth the trouble to force you to log in without it just to track you. Maybe if teenage girls were using Tor I might be inclined to agree but right now it's just not worth the effort for a few nerds.