So if you say to your employer "oh hey I've found a new job that's offering me $20k more than I'm making right now" and offer them a chance to match that offer, is that also extortion in your mind?
No, but if you say, hey, we’re all going to burn down the store if you down pay us $20k more… that’s more like what a union is threatening.
There’s practically no limit on what a union can extort from a company. If a company invests in capital to make its employees more efficient (faster coffee grinders - if we’re keeping with the Starbucks theme), then the union can demand that savings in their wages.
Unionization makes it less likely for businesses to make these capital investments.
My theory is that’s why almost no airlines have ever been profitable. All the gains in cost/passenger seat mile gets taken by the pilot unions.