Fairness is completely subjective and I notice that this is often shorthand for giving more money to those that contribute the least.
Of course there will always be those that can't contribute much due to factors outside of their control, but we are kidding ourselves if we pretend that there aren't already lots of people that are scraping by doing the bare minimum (sometimes even less) and making completely irresponsible decisions knowing the state will ultimately insulate them from the consequences.
I personally know people that have had lots of children that they can't afford and can't parent properly simply because they wanted to. They are now on an incredible amount of money as the two child cap has been lifted. I know people that have stopped working because they weren't much better off than being on benefits and they couldn't be bothered with the hassle. I know young people that are already planning to stay on disability benefits their whole lives for mental health issues as they want to stay home and game.
Is it really 'fair' to charge the rest of us more to subsidise all of this?