"I simply don't believe you had a whale of a time at a wedding without drinking." I think that says far more about you than me. I genuinely had a fantastic time, was first on the dance floor, last off and on the karaoke they had going too.
"but there would be a big hole in my life without it." If that's really true, you might want to seriously consider if your relationship with alcohol is a healthy one.
"a drinker's perspective" yes I suspect that's EXACTLY what we're getting from you.
"I don't understand why some people are saying it's becayse drinkers feel guilty or want to make themselves feel better. What's there to be guilty about? Why would you feel bad for drinking? It's perfectly legal and socially acceptable" if that person knows honestly within themselves that their relationship with alcohol isn't altogether a healthy one then someone out with them in a social situation where they will be drinking who isn't drinking makes them nervous, for a variety of reasons:
A sober person is more likely to notice just how much someone is drinking - alcoholics can sometimes add extra drinks for themselves when it's their round, or visiting the bar in between rounds, or get stronger drinks when it's their round, or have an extra shot while waiting at the bar for other people's drinks. Sometimes they'll volunteer to get more rounds in than they're meant to or to help whoever's round it is in order to do this.
A sober person is more likely to notice how NOT drunk an alcoholic is. How it takes more for them to get drunk.
Someone not drinking reminds them it's a choice, not compulsory this challenges their internal excuse for drinking in certain situations.
A sober person may notice an alcoholics otherwise poor behaviour - eg how they treat their partner when drunk.
A sober person having fun in a situation where they can't imagine having fun without a drink challenges their excuse of it not being possible to have fun without alcohol.
All things that alcoholics in my family have admitted to thinking/feeling/doing while in the grip of the addiction.