From a technical perspective I agree with you. Morgan moved under Triche after Triche had made his offensive move to the hoop. The rule clarification this year seems to describe the Triche/Morgan scenario exactly. Last night, Hood had better established position than Morgan although I still think he moved into the player.
But the big difference between the two plays was the degree of control of the offensive players. While that is not a factor stated in the rules, it always seems to have a big impact on how refs actually enforce the rule. Triche was out of control, while Fair exhibited great athleticism in moving to avoid the contact and make the shot. Also, Morgan really took a hit while Hood engaged in a greater degree of flopping. By that standard, in most cases I think refs call the charge on Triche and a block on Hood. In all cases, though, it is a 50/50 call and you cannot get too upset when one of those calls goes against you. Of course, in both the Michigan game and last night's game, the big 50/50 charge-block calls all went against SU, and that is what drives fans and coaches crazy.