I wouldn’t say that 99% of them here are pro-life, having interacted with so many of them.
As far as the ones that do claim to be pro-life, why would they work so hard for an anti-conservative movement that isn’t pro-life and that is a social liberal movement?
How many libertarians on FR support the Libertarian party? Practically none as far as I can tell. Which isn’t surprising since most are basically just conservatives who give a somewhat wider berth to individual liberty than the average conservative.