That's not my understanding at all. You can't just relicense BSD code. You can incorporate it and distribute it with your own code that's under another license, but you couldn't just clone the FreeBSD source tree, 'sed s/BSD/My Own License', and call it good.
Relicense as in add another license with whatever restrictions they desire, because literally anything aside from changing/removing the original license itself goes.
As long as you keep the previous license text somewhere and note what it applies to then I don't see the problem? FUTO does both in the NOTICE file:
>The license below applies only to the original AOSP keyboard code, which is
up to commit d847619a2b48945465f840b8d81644fa455cc115.
> Copyright (c) 2008, The Android Open Source Project
> Licensed under the Apache License, Version 2.0 (the "License");
> you may not use this file except in compliance with the License.
