Who would you consider to be "liberated"? I can't recall even some of the well-regarded teachers of recent times (Thich Nhat Hanh, Ajahn Chah, and others) making that claim about themselves, though others certainly made the claim for them.
Contrapositively, if Buddhism is even moderately well-founded, then at least some truly liberated people would totally scream that out, at least under some circumstances.
I'm Eastern Orthodox Christian, so I do find some sort of speaking out to be productive. The apostles did evangelize, they worked miracles and focused on others above themselves according to the Book of Acts and epistles. But even St. Paul, in his epistles, speaks openly and humbly of his own struggles with the flesh. While he's given strength for that battle, he is meaningfully but still not completely liberated from dealing with the problems sin/temptation present. I understand that everyone who calls for me to listen to a talk could only be liberated to a partial extent. I think once a mortal is fully liberated, they will no longer need to evangelize. Kind of like how we only have sex in this world, it's something for the interim. Until the Resurrection, most if not all of our lives are a work in progress.
I also pay attention to the examples of the desert fathers, many of whom held exceptional wisdom which caused them to deliberately eschew all company, out of fear of becoming prideful by asserting spiritual/intellectual superiority and taking control of the lives of the people in the cities from which they fled.
Where you said "Fuck, I don't know! Ask someone liberated, not me.", I might say "Fiddlesticks, I don't know! Ask someone further along the path with a teaching mission, not me."
By the way I don't if you were aware or not, but this man, Father Seraphim Rose was actually a former student of Alan Watts. I find his writing helpful, personally.
Except that probably most Christians think Shakyamuni was, at best, mistaken about all that stuff, and Jesus wasn't.