GPL can also turn manufacturers away. I would rather have variation in the possible BMC operating systems instead of sticking linux everywhere and contributing to a monoculture.

...which you wouldn't get with BSD as they'd just close it down and ship you binary, as they would have no obligation or reason to.

The BSD "freedom" is not for the user of the software, it's for corporation to take.

And how would this affect the original open BSD-based BMC firmware which would be available? If the corporations want to maintain their own fork, it's on them.

The original BSD release will stay open and free for everyone to utilize.

How can you trust that a closed source OpenBSD fork is secure when there's no way to audit the quality (or lack thereof) in the firmware the vendor gives you?

If it's GPL you can at least interrogate the code release and make an informed decision

The same way I can trust all the binary blobs vendors stick into GPL-licensed systems. How do I make an informed decision about those?

Software diversity is a luxury customers won't pay for.

That sure sounds appealing to manufacturers.

Once it reaches critical mass it is appealing because the value you receive from the community is far greater than what you have to give back.

If the point is code diversity, what stops you producing a fork of BSD for BMCs under the GPL?