I think I kinda understand why this is a good thing, but can you explain like I'm five? Basically, why would it have been bad to let the 0.8 chain continue?
Is the reason that it'd "force" older users to upgrade and that's a mean thing to do?
The main reason I see to go back to 0.7 instead of forcing upgrades to 0.8 is the size of the total mining pool. It should be easy for miners on 0.8 to fall back to previously used software - presumably they've all used 0.7 in the past. But miners who haven't upgraded yet haven't tested their systems on 0.8 and all manner of problems could occur making that take a long time. So we would end up with a significantly smaller amount of miners.