I guess it's the abstract, evangelical nature of it that makes it comparable to religion in some ways.

The implicit assumption you're making is that developers are not making an informed decision already. I reckon that's not the case, and the developers are informed – they just don't care.

Arguments about long-term, abstract concepts like enduring freedom of software, or the risk of patent litigation for using non-copyleft software, are valuable to have. But these things have a limited impact in the short-term, day-to-day work of developers.