That's a curious world view. People should be embarrassed by things you personally find disgusting, even if they're within accepted social norms? And you are amazed that people do things are socially acceptable? Pardon me if I say that I find that a bit self-centered.

I'm not sure where you live, but at least in the US, it's acceptable to discreetly blow your nose in many public situations (the dining table not being one of those).

For full disclosure, I should mention that my nose runs a bit more than most. ;)