>Big time the loser there is the environment for literally any bovine farming.

Factory farming probably does cause externalities that aren't addressed. People could choose to buy from grocers who only source from smaller farms but there isn't as much interest in that due to price sensitivity.

>...and since you can't support yourself on minimum wage I see that as her losing.

Even in the case where you didn't tip, she likely would have preferred having the work than there not being a job available at that location.