The problem is that if you are a non-drinker it isn't all swings and roundabouts - it doesn't work out in the end.
I agree that yes it does look bad to complain about paying extra. I quite strongly feel that therefore the onus is on the drinkers to offer that the non drinkers pay less (as appropriate).
My friends know I don't drink. They are lovely women and always make sure I'm not out of pocket. They profit from lifts home as I'm usually driving so it's all good.
However I went out a few times with a group of women from a group I used to take my children to. The first time we went out my meal came to £15 including soft drinks. They split the bill evenly (even though some of them had steak or scallops). I ended up paying over £30 not including tip.
I was seriously peeved but paid up politely, thinking it was a one off. I also went out of my way to run three of the women home.
Next time I went out with them the same thing happened. After that I was always 'busy' on their nights out. For those who say a few quid is worth it for friendship sake, well no it wasn't. People who I want to be friends with are considerate enough not to take the piss and have me subsidise their drinking (and perform a taxi service).
Work nights out can be deadly. I was on one where some guys were being very macho about the size of their wallets and ordered expensive wine, brandy etc. When they split the bill the girl opposite me (dept PA) quietly handed over her share and said nothing but she was white as a sheet. I caught up with her leaving and offered her a lift home. Just as well she was about to start walking home (at 1am) as they'd effectively spent her taxi money on their brandies. She lived quite a way outside the city centre - it would have taken her hours to walk through some dodgy areas.