I don't see that a discussion on BC can be a touchy subject; it is what it is and there is nothing subjective about it. Yes, people can get lost in the minutia of the subject, and that can make for fun discussions but it's not like discussing the merits or lack thereof of the .270 Winchester or a discussion on barrel break-in or cleaning methods.
All bullets slow down in atmoshpere and gravity pulls them down to earth. BC is just a measure of how fast that's going to happen and what it does to the trajectory of the bullet and this happens to all bullets. As the OP says, ballistics is well-known and has been around a long time.
To my mind, bullet manufacturers advertise the G1 BC value because it's a higher number than the G7. Sierra is to be commended for taking the time and making the effort to educate the consumer about how the G1 BC values change depending on velocity. Berger is to be commended for publishing G1 and G7 BC values, thus furthering the education and presenting us with more complete data. Hornady should be chastised for publishing inflated G1 BC values for their bullets. Bring out the wet noodles.
Just like the OP explained, I also used JBM to narrow down my bullet and required MV for my game, and I used the come up values to get on paper at the various yard lines and I refined from there. This method saved a lot of components and barrel life, in other words: money.
