There are numerous programs other than PGP and there are past PGP years and there will be (probably) other years for PGP itself. You're making it sound like PGP 2019 specifically and only is a major hassle for CIC.
It is completely legitimate for people to ask for information about a program they care so much about, and it is NOT legitimate for CIC to not provide such information when it's available. Of course they know when they're planning to send the invites, at least tentatively. The questions are directed at CIC in general, not at the social media team. The extension of that argument is that they're stonewalling us. The people we can contact don't know the answer (social media, call center) and the people who do know the answer can't be reached by the general public. I also don't understand the argument how there would be other questions if they posted this. So what? This specific question need to be answered because they have this information. They don't know when AORs are going out but they do know this.
The tax deadline is the latest, not the earliest returns can be submitted. There are plenty of people who already have their NOAs. If that's what they're waiting for, they can share THAT. If there's anything official on that, please share the link. Otherwise it's more guesses picked up and repeated by the many you refer to.
Most of the questions on Twitter are "I want to come to Canada". Following that logic, all immigration programs should be cancelled because they won't want to deal with the aggravation, right? They don't get to decide that. Also, right now, they're could extremely easily reduce aggravation for 27,000 individuals.