I am sorry, but I don't understand: why is it okay for Microsoft to use to BSD code, without giving BSD any credit, but not Linux?
My understanding is: the ISC, MIT and BSD-licenses allow for sublicensing without making any modifications so the Linux devs are perfectly within the license when they sublicense the original code under the GPL. Theo de Raadt is wrong here.
Also, my understanding is: Theo is wrong about the license change only affecting source changes. It also affects the original source code because the licenses explicitly allow for this. If the licenses did not explicitly allow for this, he might have had a point here.
Also, I am not sure that Theo is justified in ranting about "the Linux people" when this was one incident that happened about 15 years ago, and was corrected.