I’m not too sure about all this clutching of pearls 
My current stats are that I fold 74% of hands, win without showdown 63% of the time and win 37% of the hands that get to showdown. I know my win at showdown rate is pathetic - I blame alcohol lol -but even so, that leaves a really small number of hands played that are available to the players at my table to analyse.
As @AKFolds implies, this is beneficial more than harmful in my opinion - anybody who uses my showdown hands, win or lose, to “read” my range will soon “learn” that my entire playing range is 88+, A2s+, suited broadways and, occasionally, 98s+ !
Please just assume that is my entire range and come sit next to me!
So, having said that, and reading what the much better players have said, I don’t know what I don’t understand about this change.
If I call on the river then I am “paying” to see what my opponent has and vice versa. That seems perfectly reasonable to me. There may be some room to debate the “right” of the other players to see my hole cards but I don’t see anything unreasonable about the players involved in the showdown seeing what the other person/people have.
I can’t see any data mining opportunity here because viewing the hole cards is restricted to players who “were involved in the hand” (whatever that means!). Nobody who has participated in this discussion (so far), for example, can see any of my losing hands.
So, would some kind person please explain why this change is so bad?
Regards,
TA