More or less agree with your other various commentary, with the add-on that many of these issues are akin to 'settling out of court', if you make a reasonable but generous offer early on in the battle it diffuses it. For instance I'm entirely sure that if a decade and change back the right had offered civil unions that explicitly were not marriage but granted most or all the rights of one, and allowed gays openly in the armed forces but required anyone who wished to be openly gay to be in units with greater general privacy or which were co-ed with punishment as unit transfer without prejudice rather than a court martial we'd probably not be having most of this debate right now. Many would have said 'good enough' and turned to other concerns, probably even including myself, and likely it would have rippled to other countries with similar results.

As to the libertarian streak, part of that essentially relies on libertarianism being a pretty black and white philosophy often a step removed from practical politics. Its attractive because it allows someone to have very solid and legitimate positions on issues that often get a lot foggier and murkier on close examination. I suspect that while individual issues are often generational libertarianism as a whole is something one often grows out of as one gets confronted with the real-world complexities and sucked into that. For instance, as much as I tend to lean libertarian on a lot of issues I'm just not willing to take such absolutist views on personal rights vs social norms or community interests. I can accept pot legalization but don't feel the analogy transfers to heroine, that's an overly simplistic approach and one I think that is very attractive to people who are fairly knowledgeable but not really fully immersed in the practical realities of the existing world. In other words, smart but young will often find libertarianism attractive for much the same reasons they might find full blown socialism attractive. They're just not aware enough of the practicalities and generally resent having them pushed on them since they have a nice solid philosophy to work with. Admittedly the same can be said of lots of things but its more obvious and severe for those two I'd say. Now neither of those is truly black or white or absolute, but they come much closer to it then you'd expect to see in a two-party system.