Here's the fact.. The contracts are for 12 months... by your own statement a teacher has the option to take the pay over the 12 months or over a 9 months... If a teacher doesn't wants to take a summer job that is there choice it isn't a requirement. In my Fort Worth Texas the starting salary for a teacher is a little over 43,000 a year... the average salary of the average worker in Fort Worth is a little over 32,000 a year.... Now if the average joe can make ends meet on 11,000 less than a teacher... then I see no reason why a teacher would HAVE to take a summer job unless they are just very poor at budgeting.
That may be the case where you live but its not everywhere. Starting salary for a teacher here is much lower, and the cost of living is very high. Some teachers do need to take a second job in the summer, regardless if they are getting a paycheck during those two months of summer.
The fact is it doesn't matter that they get summers off, they still deserve to be thanked and appreciated for what they do during those other 9 months.
Here's a question, what about the teachers who teach at schools that go year round. Should they more appreciated than the teachers that go from Sept. to June, in your opinion?