...Really? When I just read that thread it said the opposite.

(To be clear, I see one person saying, '"berserk, the character cannot be stopped", so I imagine general stun, fear, domination immunity.
don't know if this goes without saying, so I'll say it anyway ;) it also gives a hit point boost, which is lost when the berserk ends (yes also killing the character if it takes him below 1 hit point).
also remember that Korgan has this ability, so he also makes for a good demi-lich killer.'

So, one person who is imagining based on a description, quite possibly the description of Korgan's Enrage since s/he apparently thinks Minsc and Korgan have the same ability.

And I see one person saying, "I can tell you with certainty that Minsc's berserk *did not* protect against imprisonment when I fought Kangaxx. I don't know why, because I even have Baldurdash installed, but I watched as poor Minsc and Boo disappeared into the ground. "

So, one person who actually tested whether Minsc's Berserk conveys immunity to Imprisonment, and got the answer No.)