I believe it's a balancing decision. In the 1.0.5 lab mechanic, you could kick that report back around and ship it to a dozen labs so you can farm a crazy amount of science from that single piece of goo. In particular, it was possible to have a station with a lot of labs on there and feed them a single experiment, to mine hundreds of science points per day. There was no limit to that.
Now you can only 'mine' the science from that experiment once (although it may be possible to process it again in another lab if you go back and re-do the experiment), so you lose the data, but in return, the science payoff is greater.
It's just done to make science experiments more challenging instead of mining a lot of science points just by hauling a single goo canister to a dozen labs in the Kerbin system.
