One of the things many people enjoy about living in a care free society is being able to go out in the car and drive home whether you are sober, have had a drink or are drunk. Cars are considered security capsules by residents. I don't like taxis because I don't like to spread the word even further of where the gringo lives. Besides that, life is spuradic in DR, we tend to do things wihtout planning to, I might go somewhere, and through no intention end up drinking with people, I like the freedom to do that without concern for police pulling me and taking my license. Besides that, integration is an important part of living in another country, and I've been stopped many times with a beer in my hand and never had so much as a word about it. If they don't care then I'm happy to drive after a drink, it makes my life easier. I've never killed anyone after many years of it, everyone else is drunk also and so that's just how it is.
Not so long ago people were still drink driving in the civilized world, give the DR another 40 years to catch up. People make their own judgement of just how drunk they need to be to consider not driving, some can and some can't.