As I wrote - people have an expectation that they can go about their business and activities in public and work environments without being harassed, and that expectation is supported by law.   The woman was on the job, and the passenger's comments were "unwanted verbal . . . conduct of a sexual nature that creates . . . [an] offensive environment."   The airline, as her employer, cannot legally require that she overlook or endure such behavior, even from the passengers.  On the contrary . . . it could make them liable and vulnerable to a lawsuit if they required employees to allow that behavior.

Furthermore, I have no doubt that the passenger's behavior and behaviors like it have been addressed in the crew's training at length, because it's their job.  She was not able to have him removed so readily because she was easily "offended."  He was removed quickly because his behavior was much worse than just "childish" or in "poor taste," and others at her job agreed with her.