Let's be frank here — that's your fault.
Why is it like this? Because nowhere in the game do you offer people even a starting clue that all these resources are out there, and that these resources are MANDATORY to their performance.
It's pretty unfair, to be honest. I really don't see "It's hard to figure out and requires Google, and once you do all your research, you're much more powerful!" as compelling gameplay. It often seems to make the more motivated among us feel smug and superior, but I don't think the potential for egotism due to others' ignorance is, again, compelling gameplay.
There's a potentially valid argument that even if you make these resources obvious, the vast majority of players just don't care enough to actually use them. Perhaps that would prove true. But until you at least offer that gateway to them, it's senseless to complain about their being in the dark.
I'm not sure where to start here but I completely disagree with putting all the onus on Blizzard here because there are behaviors present that are 100% out of their control regardless of how far they go to disseminate information.
This game, is not super highly complicated. There are video games out there on much smaller scales population wise with far more complicated systems and hypothetically volumes more worth of theorycrafting as well. Taking the absolute simplest of gaming types and I guarantee you we could all sit down in a huddle and model, program, discuss, argue, and pound out each and every detail in order to optimize gameplay.
The reason extensive theorycrafting ever crops up for any given community is because... the community sinks its teeth into it. Blizzard has never discouraged us from digging into the game either and that's a plus as well. But how deep and thorough the community is with the information and theory is... well... all on us, and Blizzard CANNOT be endorsing any of us at all. Stickies get put up on forums with guides and information based on COMMUNITY feedback first, then they glance over them to see if they're helpful and useful and slap them up. That's the closest thing Blizzard can be to saying "Yeah, this poster here knows what he/she is talking about, listen to this person" without actually saying it, and even then it is a stretch and no employee will EVER go on record of saying "Yeah, that Fasc guy knows what's up, we take his advice very very seriously over other people."
You do NOT need to know the tremendous amount of theorycrafting background that goes into BiS lists and rotations in order to come decently close yourself. The game IS complicated, but it isn't THAT complicated. If you did the bare minimum of efforts as a DPS, figured you didn't want to miss any shots so you made sure your Hit (and Expertise if it applied) were high enough to cap, and then stacked your best stat (Int, Agi, Str) or even matched all the socket bonuses, and equipped the highest gear you could get because it just had more of everything on it... you're 90% of the way there on gearing. No optimization, no back and forth about the pros and cons of shifting around Haste for Crit, none of that. Just gear that's for your class, at the highest level, jammed to the teeth with as much of your favored stat.
Beyond that, information IS out there. The first thought SHOULD be to come here beyond asking friends you know online, who should also direct you here. The community has grown a lot so people skip the easy step (coming here) and often go to whatever fansite exists for that need. Blizzard endorses that better than most gaming companies, but they can't force people to come to this site and then hold their hand to direct them to the right stickies while simultaneously avoiding negative or bad posters.
I've never looked so I have no clue if this exists in game yet or not; however, Blizzard could very well have a built in FAQ for Player Tips and Tricks where they direct and encourage you to peruse the various class/role forums and make sure to read the stickies first, even example posts on how to ask questions to get good responses. Beyond that... what the hell can they do aside from having built in Fasc's BearCAD Spreadsheet that automatically tells them "Hey dude, these boots are better than those boots by this much."
The negativity that stems from people not knowing and parading the info around like it is some sort of badge of honor or as an excuse to act like an !@# is NOT Blizzard's prerogative either. People will be people and Blizzard can't help that morons everywhere on this planet will use literally any and every excuse to try to act superior over the slightest difference. The community sets the stage of "X Stat or DIE!!" and people feed off that, and we can choose to either act like information warmongers to influence poorly... or be as helpful as we can to those that come along asking and influence well.