Could Pele play in defence, no, so is Bobby Moore a better player because he could? What about in goal?
Of course Pele was a better player than Bobby Moore, but when we think of the GOAT our choices always take us to forward players.
I find the whole GOAT thing very subjective (a point you make in your post) but I also find it very childish - something kids do in the playground.
Creating is much harder than destroying. I know its very difficult to be a professional footballer at a high level, but there are "easier" positions. It's easier being defensive minded than attacking, which is why at school when teams are being picked for PE football, the worst kids are picked to play in defence, but the more gifted kids are always attackers. The likes of Vinnie Jones, and Robbie Savage carved out good careers being destroyers (almost literally in Jones' case). Also football is an entertainment, and people enjoy seeing goals scored, rather than disciplined defensive games. Goal of the month? Yes, not so much best timed sliding tackle of the month. I don't find the greatest debate childish at all, its always a worthy and interesting debate to have.