A lot of celebrities need to travel to entertain. A lot of those celebrities do not fly nearly as much as Taylor Swift does, and continue to make a living. Knowing these facts, one logical answer to your question is that she could probably fly a lot less than she does and still maintain her career as an entertainer.

It's not that she shouldn't travel, which seems to be your takeaway of the criticism of her. It's that she should fly less, or do it much more efficiently (if she needs to fly, does she need to fly separately from everyone else in her crew that is going to the same location, or can she chart 1 jet for everyone?)