I think that Google is still missing the point -- yes, we understand that webmasters sometimes use keywords/meta-tags to hijack results and we also understand that you can put a plus sign in front of a search term to disable the functionality, but that doesn't mean Google is doing the right thing here by default. It's a bit like returning results for the word "Catholic" when someone searches for "Christian": the two words are related, similar, maybe one is a subset of the other, some people might think they're practically the same, etc., but they are NOT synonymous or identical in any way (and Google doesn't attempt to do us a favor of treating the words as equals). Further, no one accidentally types one word to mean the other. All results that relate to "vegetarian" are 100% irrelevant for what we're searching for -- always.
That's why we are always appending "-vegetarian" (often in addition to "+vegan").
I certainly don't want to start a religious debate or a debate about veganism vs. vegetarianism, but, as the original post stated, it makes no sense whatsoever for a search for the word "vegan" to return results for the word "vegetarian". I realize that they may seem similar to someone who is neither, but they couldn't be more different (in American English). People are often looking for vegan restaurants, vegan hotels, vegan tips, etc., and it's insane to have to wade through totally inappropriate results. (By the way, this is US-specific feedback. You can leave the UK or other results alone, if you like. I can't comment 100% there.) Note that there are 3 million hits for "vegan vs vegetarian", so we're not being overly sensitive; we would just like Google to consider removing all of the weird synonyms for "vegan".
While you're at it, can you get rid of "vegas", as well? It's another totally bogus synonym. If you want to fix typos, Google can do the "Showing results instead for Vegas...", but don't automatically put a bunch of Las Vegas restaurants/hotels/tips/etc. in the middle of my search about vegan stuff. Please?! :-)