There's a similar controversy about radiation hormesis[1]. Personally my suspicion is that low doses are at least harmless if not therapeutic, because of the evolutionary benefits of the stress response[2]. However I do freely admit that it's possible that there is no therapeutic or even safe level of alcohol consumption. Similarly there may be no safe level of BPA exposure or any number of other stressors.

[1] https://en.wikipedia.org/wiki/Radiation_hormesis

[2] https://en.wikipedia.org/wiki/Stress_(biology)