That seems like a pretty good summation of what the writers are going for. It gels with my interpretation of Sam's general headspace/motivations, anyway.

But yeah, plotting is a big weakness. Unless the whole kidnapping/torture opener later pays off in some big way, I think it was a pretty major misstep to have that be the BMoL's introduction. If the show was going to go the should-we/shouldn't-we-work-with-them route they should've been set up as a temptation from the start--introduce some genuinely sympathetic members, have them contribute something useful, make the audience want to trust them. Then we get gradual reveals of their shadiness and have to guess at which members can be trusted and which can't and how deep the corruption goes. Basically, what was done with the angel story arc in season four.

That said, I still can't get around how anyone is supposed to buy that the BMoL are going to be the big picture saviors of North America when they failed to even show up for multiple apocalypses--apocalypses which would presumably have also taken out Great Britain. Which I get is the unavoidable plot wrinkle of introducing a new world-building element on top of so much established history--it would be really hard to come up with a seamless retcon, but they could've at least tried to handwave it.

There's also the ethical issues--the xenophobia/fascism the BMoL espouse which so far has been only glancingly addressed. Well, I'm pretty sure the endgame conflict and resolution is going to hinge on that--there's going to be an oh-fuck-we're-in-the-belly-of-beast-and-the-beast-is-committing-genocide moment. I'm undecided about which side of the Doyalist/Watsonian line I'll fall on--more annoyed with the writers or the characters when that happens.