It's not trivial to just support all countries from day one. GitHub has never done marketplace-style payments (individual to individual) before. When you're dealing with money, it's best to take a measured approach. I'm actually super impressed with how fast the team has been rolling out support for new countries.
I didn't claim it's trivial or not. The message itself is confusing. There are 3 concerns here: beta, Stripe, countries and it's no clear how they inter-relate from the blog posts. As far as I can tell now, no-beta==Stripe Countries, beta==non-Stripe-Countries and other payment options like wire transfer have no weight.
