Tell them you don't want to work in group, that you're there to learn things, not to be humiliated for having poor social skills.
If they tell you "muh we're here to prepare you for your future life where you'll have to work with people" tell them to fuck off, that they have no idea what you will be when you grow up and that the purpose of school is to educate, not to do social engineering.
Or tell them : "- Fine, you're preparing me for my future social life, huh? I guess in the future I'll have to have sex too, right ? Can I be prepared for that ? - But but muh sex is different, it's optional. - Well working in teams is optional too, the distinction is arbitrary, stop trying to micromanage society and stick to teaching us stuff like sciences or languages. Also fuck you.".
Also, it's not like they're teaching said social skills, I mean unless you think a good way to teach a kid how to swim is to throw him in the pool.
In any case, you should be vocal about what bothers you at school, don't just shut up only to whine about it on an internet forum.