Women who expose their breasts and buns to the public should expect to be sexually harassed. Are they asking to have less revealing costumes? No.
Why have NFL cheerleaders at all? Unpaid High School and College football players may need cheering from the sidelines for motivation. NFL players get millions of dollars. That should be enough motivation.
To titillate the largely male audiences. To provide skin scenery. To give people something to watch other than a boring sport played by overpaid babies and racists. And to give the "social justice" crowd one more thing to complain about.
That's simple. The sports themselves have become so dull that the teams feel a need to keep their live audiences entertained constantly.
Major sports have become so heavily oriented towards television audiences that they have large blocks of "dead" time when TV commercials are being shown and there is literally nothing going on at the stadium. If you haven't been to an NFL game for a while and you can stomach the idea of going to one next season, just sit there and notice how boring the whole affair actually is.
You'll notice that baseball teams don't have cheerleaders. That's because the game is already played at a leisurely pace and has "natural" breaks built into it with changes of innings, etc. They don't need to entertain their fans with cheerleaders because nobody goes to a baseball game in search of constant "action" on the field.
No one forces a woman to be an NFL cheerleader. The appearances outside the football games are part of the job. If they don’t like it, they need to find another job.
I believe the Green Bay Packers still use only high school cheerleaders in very modest attire for their sidelines.