Saw this NPR story earlier today, and thought I'd dash of a quick response because I felt like it.
First off, the German Purity Law of 1516, despite its pretentious naming, is an important part of beer history. Given that beer is an important part of human civilization and history, it is absolutely worth honoring. At least in the sense of recognizing it and understanding the impact it had on its society and the broader beer culture. Beyond that...whatevs.
I'm not well versed on the particulars of the Reinheitsgebot, but in general terms it says that beer is constituted of three things: [malted] barley, water, and hops. Yeast was later added to the list once scientists discovered it. Discarding the mega-corporations (AB Inbev, SABCO Miller, etc) I'm betting that a significant portion of beer made in the world follows those guidelines. Most of the time, you fall out with the Reinheitsgebot at forced carbonation. Discard that, and I'm betting a majority of the craft beer produced in the world consists only of barley, water, hops, and yeast. I'd bet most homebrew does, as well. The point I'm trying to make here is that it's not a big deal.
And, I really don't care about it beyond its historical significance. I'll brew what I think tastes good and what I think will bring people together over a pint or three. The beer drinker is the judge, not some dead Germans.