This line of thinking has been heavily questioned in recent years. People who never drink typically have a strong reason (recovering alcoholic) for which they have already suffered long term damage. Even people who “don’t drink” can be convinced to imbibe a bit on a special occasion (New Years, graduation, wedding, etc).
That assumes you'd be the same amount of social at those events without alcohol. If a beer or two takes the edge off and you're able to relax and relate and socialize and you're happy, vs you're nervous and uptight and are alone in a crowd, you don't get the same benefit. It's not called a social lubricant for nothing.
It's not any new research. Just a simple conclusion from the entirety of research in this field. All research shows that there's no safe dose of alcohol. That starting to drink never improved anyone's health. So if there's correlation between health and moderate use any causation that might be there can't go from alcohol to improved health. So it most likely goes the other way around. Or both things are a result of other factor. For example affluence. It is known that more affluent people drink more and at the same time more affluent people have better health. "moderately" is just roughly the level where damage from alcohol balances out the health surplus of whatever caused them to drink more.