It's a nonsense petition, IMO
And DH is a teacher, so I am bound by school holiday prices forever!
But really, it is just the way capitalism works: in August demand outstrips supply so prices are higher. In September supply outstrips demand, so prices are lower.
You are not "held to ransom", you can stay at home or stay with friends or whatever.
A holiday away is a luxury, not a need
The thing that bugs me is that people like OP become very moralistic when capitalism does not work for them, yet happily pay low prices at supermarkets (when competition forces prices down) or buy things in the sale at low prices when the weather means shops have not sold as much as they hope.
All this handwringing about capitalism when it works against you ("the government must intervene, prices are too high!") yet feeling clever and delighted when it works for you ("prices are low, hurrah, government back off!") just shows your own selfishness.