“Why Moderate Drinking isn't Really Good for You” — Adam Ruins Everything, 2019, 2:32 — https://www.youtube.com/watch?v=sdKlRYha_Yc

You may have heard before that non-drinkers have a higher mortality rate than moderate drinkers. This clip explains why such claims are misleading because the health problems among non-drinkers are not a result of their sobriety. For example, the category of “non-drinkers” includes people that suffer from medical conditions that prevent them from drinking, as well as people who are too poor to drink (and are also too poor to afford health insurance). Likewise, some non-drinkers are former drinkers who may have stopped due to medical concerns. When these groups are removed from the category of non-drinkers, the claim that moderate drinking is protective falls apart. In fact, the body of evidence suggests alcohol is nothing but harmful to your overall health.

As a side note, this example is similar to studies that find married people are happier than non-married people. After all, “non-married people” may include those who were married, hated it, and got divorced.

From the video’s description: There are zero health advantages to being a moderate drinker, and there's no conclusive evidence that antioxidants in wine do anything.