You say "don't care about gear"... but note that there is a big difference between not caring about (grinding for) skins and not caring about having max stat gear. Those complaining about this change may not care about the skins, but they definitely care about the stats.
And actually, I think you can divide those "who already have the gear" into 2 categories... those who dislike grinding, who spent all their hard-earned cash or karma to get what they thought would be max stat gear (and believe me, from what I've seen on the official forum, a lot of those are complaining about this change), and those who don't mind grinding anyway, who think exotic gear was easy to get, who were probably already grinding for better skins (if there were any skins that appealed to them) or they had even already obtained the skins they wanted. Having something else to grind for will not bother them all too much, considering that they don't mind grinding anyway.
And then there's the group that didn't have a full set of exotic gear yet, but maybe had a couple of pieces and were working hard to get the full set. Some of those people already felt that getting exotic gear was a grind, and they weren't too happy with that. Now, halfway through, they are told that they need to start all over again and do a completely different (and longer/harder, given the targeted mid-term goal) grind to get best gear. That doesn't make them happy... even more so as ArenaNet clearly told us that endgame would not be about grinding for better gear.
So whether or not they already had a full set doesn't really make a difference... they cared about gear stats before the update, and they care about the stats after the update. That hasn't changed. It just became a lot harder for them to get that gear.