*My responses assume that your daughter isn't missing school due to something serious, like a severe medical issue or something similar. If that's the case, and there hasn't been a discussion with school officials over how to appropriately handle missed time/work, then that should take place ASAP.*
There are a few things going here, and they need to be looked at separately in order to make any progress.
1. The grade being lower due to not being in class on Fridays: This is totally acceptable, as is telling a 4th grader why it is that way. No matter the reason she was not there, a lack of attendance hurts a grade. Now, if she is making up work and the grade is still lower, it is probably due to class particiaption points that are being missed. This teacher is (correctly) getting students to realize that just doing the work isn't enough, they need to be present and actively participating in order to get the full benefit of the class. One question: when she has missed Friday afternoons, is that the only class being missed? If it's not, and teh reading grade was the only one affected, you made need to do a little more investigating.
2. Missing "specials": Yes, it's no fun not to go to art class or music class or whatever, but with the current way schools are required to show student progress, this may be the best option. Perhaps your child is capable and dependable enough to make the work up at home and not miss specials, but unfortunately, not all parents care enough to make sure this happens, so the teacher or school does what they can to take away that variable. On the whole, missing a special class isn't going to take away from an overall education. As for finishing and not being able to go to the special, that doesn't make much sense unless the time involved was so short not to make it worth it.
3. Missing materials: I agree with the previous poster, a 4th grade should be able to attempt answering things on an assignment, if the work is familiar, whether they are missing material or not. Yes, reading and following directions is crucial, but we don't always have what we need to complete a job in life, and we make do with what we have. No a bad lesson for a 10 year old to learn. Also, was the teacher who was supervising her make up time the teacher who assigned the worksheet? If not, perhaps pointing out to the teacher who assigned the work that there are times your daughter does not have all of the materials to complete an assignment, and ask what should she do if she encounters that again. Again, learning how to creatively handle an unforseen problem is a great thing to learn, and it makes kids better all around.
4. Being upset at comments: That's totally a personal thing. I wouldn't be bothered by it, especially with a 4th grader. At that point, kids should really be stepping up a bit more when it comes to their school work, both at school and at home. Though some policies or rules may seem a bit extreme to us as parents, teachers need to keep things as structured and uniform as possible so that all students are able to benefit. I would expect my kid to understand that what they do, or don't do, at school will affect their grades, and that includes being in school and completing required work, even if that means missing out on something they like. However, I have some pretty high expectations regarding school performance and behavior, which is probably why the comments and scenarios described wouldn't bother me if they happend to my son.
Bottom line: If you truly feel it's unfair that she got a lower grade, then schedule a sit down with the teacher, ask for a very clear reasoning for the lower grade. She should be able to provide it, and if not, then involve the principal. You may not be able to change the missing specials to make up work policy, but I guess it couldn't hurt to get more details on it.