"Someone who literally did nothing but pull a lever to initiate the flow of liquid from one point to another."

Are they pulling that pint from an easy chair in their home? No, they had to go to the brewery, set up for business, and then at the end of the day they will have to clean up before they go home.

So now that we are having that conversation about tipping, if you recieve good service from someone in the hospitality industry in the USA and you don't share a gratuity with them, you're an asshole. If you stay in a hotel room and don't leave the chamber maids a little something when you check out you are worse than an asshole. That's how things are done here. Tipping is completely voluntary behavior, and gee willikers we shouldn't be exposing anyone to that. Their sharing should be systemic and mandatory I suppose.