In this TES Connect forum thread, there are some interesting views about teacher's workload and the misconceptions about it. I'm not quite sure if I agree with the OPs views or not.
So, I think the original argument comes from the fact that teacher's workload is very high, and is perceived to be very low, because of the holidays. There is a divided opinion as to whether teachers are effectively only paid for term time, despite working all year round. Salaries are calculated as if you did that amount of work only during term time, so really, for the amount of work that actually happens, teachers should be paid a lot more.
I am inclined to agree that teachers are not paid enough, but I don't think it's because it's calculated in that way. The pay is alright compared to other jobs, but considering the workload is a lot higher than other jobs, I personally think the pay should be higher. I think this is one way in which misconceptions about workload effects teachers negatively.
I love the calculation of how much time teachers are expected to spend on each student's work though. That really highlights the ridiculousness of the workload and what is expected of teachers I think. So, parents expect teachers to spend up to 30 mins on each student's work, and if it is any less, the teacher is thought of as lazy. Even with just one class of 30 students, that means an extra 15 hours work per week, and that is just spent on marking.