I do think the punishment is severe a year in the life of a teen is much different than an adult and an adult acting inappropriately is quite different than a teen. There definitely should be punishment but a year is a lot considering there are only 4 seasons of opportunity in high school. At this age they are learning what the consequences of their actions are - so punishing for an entire season is extreme - for me I'd rather have her learn from this action and become a better person, however, I doubt it with her parents reaction.
On the flip side though - if it is spelled out that the consequence for doing A is B and that is exactly what she is getting then have less sympathy. I would be curious if it is spelled out that way that profanity and inappropriate team behavior on and off the field/competition practice is a suspension for the season. If it is clear - then I agree.
The other thing is high school sports, although it does teach much as far as competition, team work, good sports so forth - is a quite a bit different than professional and even college sports. The age and maturity of the athlete and the level of competition is so much higher.
I do think though this girl's parents are doing her a disservice especially if the agreement is very clear on the punishment (even if the punishment seems to severe for the infraction). What is this teaching this girl? That if you don't like what happens when you do something wrong that you above the "law" in a sense...that all you need to do is run to mommy and daddy to have them fix it. No in the long run she would have been better off to serve her time, apologize for her actions and take accountability.
That is what I really liked about this girl and her parents from my daughter's team. And you what she re-earned her captain title the following year. She is probably a better person from this and showed real character in how she handled is.
Flip side when my daughter was a senior - one of her co-captain got caught doing the same thing. You would have thought she would have learned from this other girl. So it was toward the end of year so she ended up missing out of her senior night and left her team in the lurch as was suspended at playoffs. Her mom at one of the games - basically poo-poo'ed it and thought the school was being a bit harsh. Again what are you teaching your kids? Because in the end isn't this what it is about?