If by "ordinary, mainstream" you mean white, you need to remember that the Irish, the Polish, etc. were not considered white at this time.

(not trying to be racist, just trying to accurately describe a racist system)

I don't mean white. Prohibition agents didn't just hassle the Irish and the Polish (though they did particularly focus on immigrants). The invasive nature of Prohibition extended to everyone, across racial lines. Arguably that's why the drug war has lasted so much longer than Prohibition--so far the major injustices of the drug war have been limited to people outside the social mainstream.