Do you honestly think, that "this guy says so" is a reasonable argument or grounds for anything? Whatever Yoshi P says has no relevance whatsoever to how the game is actually played - and how the game actually works is what is relevant to this discussion, not how it's talked about. (He of course is in the power of adjusting the game in a way that changes our play style if he so wishes, but that's a separate question - although it may be worth noting that the way he and his team have currently designed the game is exactly the reason why healers are and should be DPSing.)
Erm... these are discussion forums about the healer roles in this game, meant and generally used for discussing optimal play for each role (just like the tank and DPS roles which are full of discussions of optimal rotations, stat weights, use of abilities etc.). I take part in these discussions because I'm interested in how these roles are played optimally (as an ex raid healer and current extreme/dungeon healer, but also in general), just like I follow (and sometimes take part in) discussions about how the DPS and tank jobs are played optimally. You may get various
feelings reading these discussions that direct your interpretations of them, but in this case at least your line of thought seems a bit far-fetched. It's more likely people read and take part in this discussions because they want to (know how to) play better.
