I understand they apply this method, especially considering how often rains affects the game. I see that it was introduced fairly recent, was there confrontation to this rule from old school fans? 

Yes. It's for a situation where the target score for a chasing team needs to adjusted when the overs are reduced. But when there are less number of overs the chasing team is at advantage if score is adjusted without it. 

Suppose a team scores 300 in 50 overs and the rain comes. The overs are reduced to 25 for the chasing team. With DLS the target should be 151 which is unfair because knowing that the chasing team still has ten wickets in hand the target is made higher by DLS and can be around 190 to 200. 