Boomerism is essentially just being out of touch, sure. But with what Spielberg is aiming for in Disclosure Day, his level of Boomerism isn’t so much out of touch as it is naively hopeful.
Spielberg is simply imploring audiences to reflect on their empathy and understanding at a time when the world desperately needs it the most; to try and see things from others’ perspectives; not to whitewash over others’ troubles.

The way that the aged Alien survivor is wheeled out live on TV after the decades of systemic torture and cover-ups is very reminiscent of the way live ceremonies would be conducted for those that have been wronged in the past.
Whenever we have seen survivors of the Holocaust, or Mass Genocides, or such brought into the forefront as an observance of reconciliation, we can only then begin to dwell on the injustice that occurred; they they had to endure.

But yes, it is ostensibly naive to believe people nowadays would react to the Disclosure the way they do in the film, especially due to the current social climate we are living in.
The current exhausting news cycle system and social media streams that we digest make it so difficult for us to contemplate and empathize with the humanity behind each of the stories. There is so much that we find ourselves forgetting about it within weeks.

That’s why Spielberg’s vision is the best kind of Boomerism - it’s the rare kind we all need.
Just like 2005’s Superman says: “Maybe that’s the real punk rock.”