I suppose because if you have over X amount in savings then you're not really 'in need'. Though I appreciate it does seem a hard pill to swallow, do the right thing, work, save, buy a house etc lose your job and you have to spend all your savings before you get any help, and no help with the mortgage.
But don't work, have no savings and you get everything paid and they will happily pay the mortgage of the BTL landlord...
Not sure what the solution is but it is pretty borked atm
And as Platypus says, leaving your job voluntarily is a choice, not a circumstance that has put you in need of societies safety net - well, not until you've blown all your money and are poor