Why Buddha said "if you want to remove small/light codes from Vinaya"?

In Maha-parinibbana Sutta, Buddha said "if Sanga want, after I completed Parinibbana, you can remove small and/or light codes from Vinaya". Why Buddha said this approval to Sanga? Is it a kind of testing to future members of Sanga whether they can completely comply the Vinaya or not? This approval may lead to breakage of Sanga to Mahayana, Theravada, and more. This approval, is it being served as a reference to other parties of Sanga who cannot comply the vinaya completely not to be blamed by normal people? Or is it just a question to just Sanga at the time of been said and this was the way to be. Or any purpose of this approval? Or is it totally not approval, and just question?