Not saying you're wrong, just that criticisms of Pascal's Wager have validity.
Let's be a bit more concrete about this. In the near term, reducing emissions is going to reduce economic output. That is literally going to kill people. (The stress of poverty kills people. Lack of money to pay for food and healthcare kills people. So unless you've got a redistribution scheme that you can make actually happen in the real world, reducing economic output means killing people.)
That's the other side of this "Pascal's Wager". If we run off and cut emissions before we know how to do it without reducing economic output, more people that we would like are going to die. They're not going to make headlines, because they're going to be marginal people in marginal places... oh, yeah, the same kind of people who are going to die (first) from climate change.
It may be a net win to fight climate change. But don't act like it's completely one-sided.
The physics of a Venus aren't on the table - SFAIK, all the carbon we're digging up and burning was once animal or vegetable matter, derived from a Carboniferous era level of atmospheric CO2.
I don't think we can risk this outcome (and the extinction of our race) just because because a couple of people think CO2 may not cause global warming.