Dude said he didn't want to run a vent pipe out his roof. Insulation will not solve the problem of attic condensation dripping down his pipe. I suggest a solution, I've heard no alternative solution. Maybe a flapper at the top? That would have been a productive comment.

So do nothing then and live with the drip, got it.

If the vent tube is pointing directly up, why not just put give it an s shape or a couple bends to trap the condensation higher up?

North Face arctic parka. Warm, dry and many pockets.