There are lots of reasons for the hate, although I wish there wasn't. The mindset they had when I coached and judged gymnastics was that cheerleaders were gymnasts that couldn't cut it being gymnasts. That if they had just stuck it out they could of gotten over their dislike of beam, mental block of a vault or not able to get a kip on bars. It was never that they wanted to do something different, it was that they quit to do something different. Then when they look at what they have to do versus what many cheerleaders have to do and to both be called the same thing, I see where some of their irritation comes from.
With many gymnasts, perfection before progression is not a buzz word, catch phrase or something you tell the parents and other coaches but don't practice. It is supreme law. If you break it, you just may get kicked out of the gym and potentially blacklisted from going to other gyms. It is not unheard of to work on the parts of a back handspring for a year or two before actually attempting it without a spot on the floor. In most cheer gyms the parents would of pulled their hair out, weaved it back in and went to a new gym if Suzie wasn't doing it on the floor in 3 months tops.
In gymnastics you are out there all by yourself. Everyone sees you. Where in cheer you can be creatively hid, which makes many parents not understand why Suzie just can't try her new skill out anyway. After all they are not paying all this money for her not to compete it. In gymnastics you can't bribe, berate or threaten a coach with leaving to put that BHS in a routine so Suzie's grandmom who can only come to one competition in Suzie's career can see her grandbaby throw a BHS to her cranium.
Looking at the BHS in cheer we don't expect a Level 2 BHS to look like a Level 3 BHS, Level 4 BHS or Level 5 BHS. So we have mental allowances for age and level. If a BHS looks too good in Level 2 we start screaming that athlete or that team sandbagged and should be in a higher level. In gymnastics they train every BHS to look like it is an elite BHS, period. After all it that is what it should look like, make it look like that now, not later.
In cheer we take kids that are good at tumbling and have them teach tumbling classes, open gym to work off tuition and scholarships to our World's team. In gymnastics that usually never ever happens and if you are not properly certified and credentialed you might not even get on the floor, except in a smaller, newer program. ***The using of athletes and calling them coaches to pay off a bill you created is a pet peeve of mine***
In gymnastics a handstand in California is the same in Maine. A back handspring in Florida is the same in Washington. The training methodologies, expectations, and outcomes don't change much, with the exception if the gym follows a particular training regimen developed in other countries. In cheer a janky BHS in one gym that is not put in a routine is thrown into the routine immediately in the gym across the street. Made Level 2 team and you want to be on Level 4? You don't have to work harder just change gyms! After all it was the gyms fault that did not recognize that Suzie would work way harder if she was put on a team where she had to have a skill, instead of a team where she could actually perform the skills she currently has.
The skills are judged exactly the same no matter the competition. The value or influence or subjectivity of the skill never changes - only the execution. Where in cheer it changes from week to week depending on where you are competing, who is judging, whether it is a stage or on the floor, the lighting and if they were out of dipping dots before your team performed.
The higher you go in gymnastics the more hours you train - in some cases upward of 25 hours a week just in training. In cheer we want to be on the highest level teams and spend the least amount of hours possible in the gym. Conditioning is mandatory - every practice no exception. Many gymnasts condition for 30 min to an hour BEFORE they even start their practice, where in cheer it is optional if we can fit it in because we have a new pyramid piece we just have to work on tonight. And some parents complain if you condition more than 5 minutes.
In gymnastics the younger you are, the better and the more opportunities you are given for better training. If you start gymnastics late usually by a certain age, the best you can hope for is some rec training, unless you are just that determined. In cheer you can start at any age - which I love.
Personally I love both, but wish cheer was a little more form based and gymnastics was a little more fun.