He doesn't agree that they are disparaging terms - for instance,:
the term “princess play” is not intended to be disparaging. I do not think that playing princess is a shameful activity. If you do, you might need help, because you’re criticizing a very common childhood game. The name comes, of course, from the common role-adoption game that children like to play, which I believe to present a creative agenda that is essentially similar to the enjoyment a roleplayer gets from a role meaningful to them. That is, it is exciting to pretend to be a princess or a fireman or rock star or astronaut or whatnot because you get to pretend to engage in exciting activities and be treated differently from usual.
Page 2 of the 2014 D&D Basic Rules says that D&D "shares elements with childhood games of make-believe." Tuovinen is elaborating on that point.
To be honest, to me it seems that a lot of the objection to "princess play" or "dollhouse play" is because men don't like their pastime being compared to something that girls do.