It's "needless drugging" if it's policy to sedate absolutely everyone regardless of need, hence why a lot of Trusts only offer if it's specifically requested.
It's not about being "brave", it's just a question of how different people view it. I'd far rather have a few minutes of discomfort than be sedated, but that's fine for me because I'm in no way perturbed by the prospect of gastroscopy. Of course people who feel differently should make whatever choice suits them, but it's still in no way "barbaric" to expect most people to be able to tolerate a few minutes of discomfort rather than be administered an anaesthetic.
It's not painful, it doesn't cause any damage so there is no healing involved, and it's over as soon as the probe is withdrawn, so again, for a lot of people sedation would just be a wholly unnecessary and unwelcome extrapolation of the unpleasantness.