Think about it in a different way: What if a vulnerability was discovered in TLS and FOSS implementations patched it, but there is an embargo for supposedly protecting some banking software? What if NSA/CIA/other agencies find out about it (they would know immediately) and use it to target users/activists?
But pretending as though co-ordination of any kind is somehow bad (and then resorting to emotional arguments and so on) is pretty reckless.
> even users of non-proprietary projects
Actually many FOSS projects get only notified on the disclosure date.
Hiding the vulnerability for such a long time makes more harm good. The vulnerability can potentially be exploited by security agencies that necessarily know about them and could also be leaked to a bad actor by an employee of one the vendors.
Hopefully WPA2 isn't that important, but potentially security sensitive users trusted something that was known by some to be vulnerable for 3 months! Bad actors could have used it against them.
The embargo resulted in potentially bad actors knowing about the issue, but not vulnerable users.
Do you seriously expect the other billions of people on the planet to be that great too?
No. I also don't expect them to choose device based on security. That is very bad as vendors won't care about patching their older devices (look at Android devices, home routers...) and vendors won't care about patching their flagship devices fast as they have the possibility to request very long embargos.
Making compromises for those vendors and giving more time for security agencies and other bad actors to silently exploit the vulnerabilities (where FOSS projects would have made patches for users that care) is not the way to go. That philosophy actually makes everybody less safe.
If you don't agree with an embargo and decide to break it, that's on you. But the consequence is that you shouldn't be surprised if next time you're informed later, or not at all. What OpenBSD proponents and developers are doing right now, is damage control. It may work this time, it may work next time, but it won't keep working every time so pick your fights right. It isn't the first debacle OpenBSD has with full disclosure either (hint: OpenSSH).
There are also millions upon millions of devices which won't get patched. Given the vulnerability is apparently the most vulnerable on Linux and hence Android, do you think all the smartphones running Android 4.3, 4.4, 5.0, and 6.0 will be patched [1]?
[1] https://en.wikipedia.org/wiki/Android_(operating_system)#Pla...