My two pence:
the main complaint seems to be on the subject of fairness.
The benefits system is not fair...
there are cliff edges all over the place, bandings where a minor difference in circumstances make a huge difference in income (such as 24 hours vs 23 hours part time work to name but one)
the taxation system has plenty to offer in the way of similar...
complaining about arbitrary and unfair limits ....they are all over the place. that's the way it works.
to complain about the way one benefit is done being unfair...well They all bloody are!
if you are in that higher-rate tax bracket, you are at least better placed to suffer than unfairness than most.