Very few people have the job flexibility that many of us here on HN have. This may be the best-paying job available to this person, or the only job they were able to get that they can effectively travel to -- regardless, given the unpleasant nature of the work, it's unreasonable to assume that they meaningfully "chose" the job without additional evidence.

It's not exactly working for the Spanish Inquisition. The guy was annoying and wasted 20 minutes of the client's time. I wouldn't say it's ethical, let's not overreact.

Sure, but you're not going to hurt the Death Star by screaming at one of the welders and insulting him. How does that help anything?