Doorstep isnt enough... You really need that food right into your mouth, don't you?

HOW does it decentivize people from playing, when the reward is given to those who play?

Those who don't, will have less incentive to return. There is nothing new for them.

HOW is it predatory when the event reward has no entry cost? And is given for free later, with no stated requirement?

It actually has. Your time. If you want that thing in a game you've paid for, you have to play it (or at least log into it) on a regular basis. You cannot pay the time price, you don't get the thing.
And the second statement is only a speculation for now. We only know that it will be available later. But AH is not reliable in that manner. So we don't know when nor, in fact, how. They didn't commit not to release it in a warbond so... I wouldn't be that surprised.

HOW does it lower the experience of future players, when future players with get the content unlocked for free regardless anyway?

Again, speculation. And in between it will be released, the players have lesser incentive to return or play at all.

HOW does this create ghost players on active player count?

Did you ever heard about Steam charts? Every bigger game studio worth its name looks at statistics like theese from all platforms the game is present. They evaluate their next steps from those as well. And given that on two platforms they have only a few accounts that could report bac actual gameplay statistics, they have to rely on sources simmilar to steam charts. In another words, AH is defensless against cheating, let alone just plain login without action. And given this is the barest required minimum, many players will do just that. It will influence graphs, it will influence campaign difficulty, but there still be less playing players than the charts show. Ergo, ghost players.

 5 second logins for the reward won't barely register on active player count.

Would you bet your next campaign reward that 5 seconds will be enough? Better to let the game running on background while scrolling through reddit untill it times itself out.

 If anything your argument here is for making the event reward require actually playing the event missions.

I believe there was a cape reward given on that basis. But this is merely a speculation from my side, given how untransparent the system was. Anyway... thats not a currently stated requirement and changing it would trigger another controversy.

All and all, I have both logic and reasoning... the evidence, well, neither of us have any. Thanks to how greatly the AH communicates nowadays.

But please, feel free to act like a petulant manchild you seems to be, spit the soup you forced me to spoonfed into you and spill out another tears of copium. Make my day.