That ideological purity is the entire point. The Free Software movement views non-free software as a moral evil on par with human slavery. Obviously in that context, tolerance for it in any form is unthinkable, and the only moral goal is to teach the world to find non-free software reprehensible and work towards its complete elimination.

If you're not willing to buy into the ideology, fair enough, then you can slot yourself into the Open Source camp.