Good teachers do work hard, but my overall perception is that unlike other professions such as doctors, firemen etc what teachers actually do isn't always clearly transparent to parents.
From a parents point of view, school reaching only builds upon a foundation already put in place by the parent - of course i'm talking about decent parents here- who will already have taught their child to read and write, taught them the basics of maths, taught them lots of general knowledge. Teachers build on this, but then the parent sorts out homework too, puts in extra effort to help with exams like SATS e.t.c. may give added support to the school besides this, and may have to volunteer to accompany school outings due to staff shortages. School can spill over into home life alot, epecially when parents can now face fines for school related offences i.e, taking holiday without permission, truancy etc.
And a parent may have to do all this whilst working 9-5 themselves. So in my opinion I can understand why parents may have little sympathy when teachers announce an inset day bang after a 2 week break.
And while school may not be officially defined as childcare our economy is unfortuantely pretty much dependant on schools providing supervision of children for an average of 6 hours, so dependant that yes, it does now function as child care too.
Not saying teachers don't work hard, but parents do too, and school should start reflecting the modern world a bit more as well as provide more choice within the system.