The exemption you quoted very specifically says it applies "if you combine or link compiled forms of this Software with software that is licensed under the GPLv

The exemption you quoted very specifically says it applies "if you combine or link compiled forms of this Software with software that is licensed under the GPLv2 ("Combined Software") and if a court of competent jurisdiction determines that the patent provision […] conflicts with the conditions of the GPLv2" (emphasis mine). I don't know how you could read that as applying to situations where nothing is licensed under the GPLv2. In other words, it sounds like this would address OpenBSD's concerns if OpenBSD were GPL-licensed — but it isn't.