I think you're arguing different things. I don't think Colin'smum means that this is just one mundane repetitive task in amongst a pattern of learning and our precious kids can't bear to be bored for even half an hour. I think she's saying that this is a extension of a day in which they are not challenged and this extra non-challenging work is taking time from when they could be learning how to actually work at something.
I agree that the non-challenging work is taking time away from challenging work. I think my point was mainly the fact that I am not going to tell my children they don't have to do their homework just because it's not challenging. And as a parent, I am not going to tell the teacher my child is not going to do his/her homework because it's not challenging. Instead, I am going to work WITH the teacher to see if there's something that can be worked out.
Luckily for us, DS's homework takes maybe 10 minutes each night, and most days he has it done before he comes home.
I'm sure I'm not the only parent here who learned the fine art of doing exactly nothing at school and walks away from anything that might pose a challenge. I don't intend to let my kids develop the same problems I have.
Oh believe me, you are not the only parent. I am not about to let my DC become me!

I just feel there is something to be said about teaching my DC to do what is expected from school, regardless of the level of difficulty. If more challenging work is needed, then we go to the school, the teacher and/or do it at home. DC do not just get to choose not to do an assignment because it's not challenging.