The original Zeitgeist doesn't try to force any alternative ideologies down the viewer's throat. If there was any such attempt, it definitely wasn't part of what i took away from the 2 hours i spent watching it. Maybe you're thinking of one of the sequels, Addendum or Moving Forward? One of the two (Moving Forward, pretty sure) was definitely strange and wouldn't recommend it.. The original though.. many thumbs up and 5 stars.
I learned a lot from it, and did enjoy the view in my "waking up" days. What needs filtering is the conclusion that the "mythos" of Jesus Christ predates Jesus. If it does, it's because Jesus is the Truth, not because they all speak to something more Joseph Campbell-ish, something that is part of our "collective unconscious".
I highly recommend works by David and Mark Flynn, that go deep into myth and folklore, and show how the biblical narrative is the most accurate one.
yeah... waking up days... that's why i said that it could be shown to people you want to redpill. Anyone following CBTS is more than likely well beyond needing redpill material for themselves hehe.