No, that's not what beta means. I expect core functionality to work properly in a beta. I expect there to be intermittent issues, and I expect advanced/fringe features to maybe sometimes not work. I expect there to be workarounds for most (but not all) issues that crop up. But the freakin' main menu didn't work. How is that beta-quality? I'd hesitate to call it alpha-quality.
And yes, I know, it's open source, it's free, you shouldn't feel entitled. I know. I wrote and maintained open source software for 5 years. But c'mon, from the perspective of the developer, have enough pride in your work to at least do a little testing before throwing a release over the fence.
2. The article is a bit vague (which doesn't help its case), but if the bug is the one I'm thinking of, saying that "the main menu didn't work" is a bit of an exaggeration. I believe the actual issue was that the main menu didn't work in Explorer. Broken Explorer support is very common among beta software unless they're specifically targeting Explorer specially.
I expect bugs, yes, but the "traditional" meaning of beta is that core functionality is done and it's passed through QA and some form of alpha stage with internal and some trusted external testers to catch, at a minimum, glaringly obvious stupidity.
I'll excuse a beta release with some significant but not absolutely critical feature clearly walled off and labelled "this bit doesn't work yet". I'll not excuse one where critical functionality becomes clearly unusable just by virtue of running on a supported platform. That's so beyond the pale for what is -- even if in a twisted/attenuated sense -- a commercial product as to reflect nothing less than utter incompetence.
If Wordpress was mission critical for my business, after reading this article I'd be investigating their build process very carefully. If it turns out that they don't have an effective test phase, I'd be migrating my customers to an alternative as fast as I could.
I agree that WordPress's issues multiply in proportion to how much you want it to do, but the fact that prerelease software has bugs is not one of them.