On the one hand I agree but on the other hand I think group work is an important skill to learn. This will be almost always necessary in a work environment.
I think a good compromise is to require each team member to be responsible for an identified part of the group work so that the teacher can adequately grade each individual.
At that point you're not doing group work. You're doing individual work with differing assignments.
Group work is the reality of the world. You can be the best and your company can fail because of crappy peers. Speak up, lead them to greatness and give them the boot (ie, tell the teacher) if they're hopeless.
I think a good compromise is to require each team member to be responsible for an identified part of the group work so that the teacher can adequately grade each individual.