I'm not sure I fully agree...
I can see how it's a struggle, but I'm taking into account Universal Credit is comprised of several benefits rolled together, so while as a parent or in certain housing you might qualify for assistance, a large part of universal credit is based on you being available and willing to work full time which you can't be if a full time student.
By all means ask them to reconsider the state of things, but I don't think asking for 0 reductions is realistic when others peoples income gets reduced for X,Y, Z - It's also v hard to use the 'improving myself and my earnings' argument without essentially claiming that people already going to their work (and paying taxes) aren't.
(You'll know this better than me, do your benefits get directly reduced by the student loan amount, or is it a '55p in the £' thing like workers?, if they take it off in full that's a bit much imo)