There are markets where a B2B sales representative who does not drink would be utterly ineffective as many potential customers won't even listen to their pitches without an alcohol-filled setting, and would not take them seriously if they would organize such a setting but don't participate themselves. The same applies for existing customers, they would refuse meetings/pitches/deals if they don't "have contact" with the assigned representative, so being a non-drinker makes someone unemployable in such roles.