I already see some trying to have it both ways in this topic. Look, if you want to come from an original D&D perspective, and fight for D&D "purity" (whatever that is), then it is possible to do that without dancing with hypocrisy. I think the, "we made up stuff that we thought was fun," crowd has an argument against you, but you certainly can make a
consistent argument for what should be done, versus what was done.
By the time the 2E designers had started grafting on things, though, it is getting difficult. By the time 3E came out, and it's "rule for everything" push? Too late, the purity ship done sailed. Once that's been settled, now we are merely discussing price.
Hypocrisy? Hypocrisy is all the folks that were just fine with D&D
changing into something that they wanted, but screamed bloody murder about "not being D&D" the moment it
changed into something other people wanted in their D&D all along. Note the "and", please.
There isn't a whiff of hypocrisy in Mearls' statement. He is coming from a avowed and strong position of advocating for change and expansion in what is D&D. You can criticize that for being a bad idea if you want. You can criticize it for advocating more change or different change than you think is a good idea. You can advocate for a certain amount of change, or lack thereof. If you support change and expect it to always be the ones you want--well I don't know what to tell you.