I have no sympathy for Starbucks or anyone who pays $7 for coffee.
No problem at all to hate Starbucks or their products, but there are more productive ways to express those feelings than taking it out on a frontline worker who is just trying to do their job like the rest of us.
If, hypothetically, this guys end game is to hurt the bottom line of Starbucks, at least leave the baristas a nice tip because they doing extra work that is effectively running them out of a job. Be mad at the company, be mad at the leadership, but leave the workers out of it if at all possible.