I will say I didn't disagree with DHH's use of "open source" as I will generally let it slide as its not "Open Source", the version that I attribute to following the Open Source Definition as set out by the Open Source Initiative
I agree that there are many who don't understand the distinction and assume that "Open Source" == "open source", and so I do agree that avoiding the use of "open source" where it instead means "non-OSD" makes sense