Yes, as you (sarcastically) imply people do indeed try to use QF to make actual decisions, not recognizing the proofs are based on assumptions that don't match reality.

There's nothing wrong with making proofs based on simplifying assumptions. A lot of incremental progress is made that way. The problem is not the QF theory, it is that people are using QF in the real world because they think it has all these great theoretical properties in the real world -- not recognizing that the underlying assumptions are unrealistic.