Virtualenv bin/activate isn't doing anything "wrong". It's just not doing it how the author believes is best. Can the whole "You're doing X wrong" meme die already please? I like the idea though! From what I see so far the author makes a good argument for using a subshell rather than setting and resetting environment variables. At the same time though, I haven't enough experience with his suggestion yet to see the do…
Can the whole "You're doing X wrong" meme die already please? You clicked through to an article you wouldn't otherwise read. The meme persists because it works, and complaining about it just makes it more effective. (I didn't click through because I don't really care if X is doing Y wrong.)
It does work and it makes me hate it even more! Because by the time something really is wrong I'll be immune to the meme and I'll never know what's wrong.