They're benefit bashing for votes.
They are MP's who for the main part have had a privileged upbringing. Why can't they talk about their plans for the UK's defence in light of ISIS and the Ukraine? Why don't they talk about foreign policy and/or their plans for the EU? Why don't they speak up on green issues? Why don't they discuss immigration levels or London house prices? Or even patiently explaining that benefits aren't that large a portion of expense.
Why, dear god, with their education do they lack empathy towards people already living on the lowest levels of income and have no innovative suggestions to make? Clearly original thought and critical thinking wasn't on their curriculum.