I really don't see any problem with this goal of Hilton. It's not as though they are saying they want fewer Gold and Diamond members. Moreover, what does a Silver member prevent a Diamond or Gold member from having with their stay?
And I will say that over the past month or so, I have seen an aggressive effort at hotels to get guests to sign up for the program (like discounted parking fee for their stay and/or coupons for drinks at the bar). I've noticed this being done at a few hotels while I was in line to check-in.