I just don't like quoting such long posts in their entirety, because it makes reading through the threads really cumbersome
Erm, no. You're constantly trying to present your assumptions as facts. and no matter hard you're trying, that won't succeed.
And yes, I did pay attention, and my observations don't match yours of wild speculations about inbreeding, coloring them as mad tribals with no sense for rationality, etc, while there is nothing to back that up.
You're just desperately trying to construct a justification for your actions, and fail to see how ridiculous you're getting at times.
You have to do this, because the person who told you to wipe them out, didn't deliver a sensible rationale for it, other than "There is no room for these people in my world, kill them".
So, you try to fill this void House has left you here, mainly by insinuating the worst of the worst, in terms of their perceived motives and intentions, but apparently this is not easy.
Because in the end, it's still you who slaughtered a complete settlement of men, women, old and young, for crimes they did not commit, and deep inside, you're well aware of that

Sleep well, my butchering friend

I've said it before, it's justified and I've said it before, I'd have made the same move (shock horror for you here, my first playthrough was independent, I killed the BoS. You're right, I'm a sheep, what can I say? erm...wait...)
It is justified. As for the BoS being inbred tribals, well they never absorb anyone outside of their group in, it's surprising more of them aren't wandering around with teeth in their hands. They don't accept outsiders (unless it's the PC, mostly because the PC can basically walk through lava without a burn) and I don't see any magical cloning facilities...
It is the worst case scenario, that's the point. Best case scenario is they go back on all precedents and overnight they change into wondrous people.
That just isn't likely. They're bandits, they steal technology that they want simply because they believe only they are worthy of owning it. They're willing to murder anyone who stands in their way (hell, the aforementioned exception to their no strangers thing has an explosive device strapped to their chinny chin chin) and will kill you if you refuse to talk to them.
Seriously. I went there, they came out and said come in and give us all your stuff, I declined and they tried to kill me. Now granted they may have had ESP, I was intending to go in there and murder them all but they still decided to kill me because I refused to give them all my stuff and enter their base.
I also don't understand your seeming peeve with House, you are aware every faction either murders regularly or condones doing so except for House and Yes Man dependent on your actions. Yes Man wants you to murder at least one group and House requires you to murder one, maybe two if you play your cards wrong. The NCR are worse than the BoS for taking what isn't theirs (Helios One? They want it, someone else has it, so they murder them all, what friendly fellas). Killing House because...well because they want Vegas, their unending desire to muscle their way in to as much territory as physically possible without actually doing anything with it. They are land grabbers, led by morons with the tactical ingenuity of a newt.
Legion is worse in terms of killing people, let's face it their Raison d'être is pretty much capture the world, at least in the Mojave all they seem to want to do is take over and oust the NCR, House, BoS and anyone who stands against them.
Have fun on your high horse, we're all laughing.