Most of the fans that have a problem with the PG rating, most but not all, are the ones that are so stupid to allow themselves to be so closed minded when it comes to what a PG rating can mean. For some strange reason, there are any number of wrestling fans that stupidly believe that something that's PG means it's specifically geared and aimed towards targeting children. These same fans seem to have it in their heads that R rated material is the only thing that can qualify as quality for some strange reason. If I were to list all the shitty R rated programming I've watched over the years, I'd be here all day naming them off and why they sucked.
As we've seen over the course of much of the past year, the WWE has injected a generally edgier feel into things without going over the line, including injecting some truly adult themes into the build to WrestleMania. We've seen more swearing in promos, more intensity in some of the promos, and that's been a good thing because WWE hasn't gone overboard with it. Back in the Attitude Era, some of it was a lot of fun and some of it was just flat out unnecessary. The edgy & controversial stuff got to the point where it was being done just for the sake of controversy rather than have an actual purpose to it. Now that I certainly don't miss because it led to some of the worst stuff we've ever seen on a pro wrestling television show. The WWE doesn't use blood often at all anymore, nor do the wrestlers curse every other word when they talk on the mic. But when they do, look at the response it gets. Look at how great the overall reception was for Cena vs. Lesnar. The women don't compete in bra & panty matches or pillow fight matches anymore, they're no longer portrayed as brazen ****s. While it'd be nice to see the Divas get more serious attention and be more relevant, at least lots of time isn't taken up with them. Those bikini contests and lingerie matches were nonsense and would go on forever. If I have to put up with nonsense, I prefer getting it over and done with as soon as possible. Portraying women in that light doesn't get it done anymore. All you have to do is look at TNA's attempt to start its own Attitude Era back in 2010. Women were treated as the Divas were treated, blood popped up in every other match, guys swearing constantly in their promos, etc. TNA went overboard with things and it turned off a lot of people. Edgy does not automatically equal good quality.
I think one thing that the OP has neglected to mention as it pertains to the PG Era being the most criticized in WWE history is that most of the criticizing comes from the IWC. MOST of the criticizing almost ALWAYS comes from the IWC for one reason or another. Even when WWE delivers a slam dunk by giving pushes to internet favorites, to giving them solid & lengthy title runs, to delivering interesting feuds & matches on television, to delivering great ppvs; the criticism never stops. Even when the collective IWC seems to get what it wants, someone seems to find some new angle in which to deliver the hate and many others jump on the bandwagon.
If it's not the PG rating, it's John Cena. If it's not John Cena, it's CM Punk. If it's not CM Punk, it's Daniel Bryan or Brock Lesnar or Triple H or Randy Orton. I can understand if someone's just not digging the product since you can't please everybody, but the PG bashing has really gotten incredibly stale. It's the same old arguments that've been discredited time and time again. Like most of the usual suspects when it comes to the subject of WWE hate, the PG rating is a convenient target.