I don't necessarily disagree, but the way it is calculated now leads some people to make posts or think like Dereood apparently does. More to my point, hitting HR is an incredibly valuable skill that is extremely important in the current MLB environment. I think there is a some amount (maybe a lot in some cases), of measurement error when it comes to defensive value. Schwarber is a bad LF, there is not doubt about that.
I don't know what to do about guys who play significant games at multiple positions. There is value in that ability in itself (except for if DH is the other position).