I'm sorry that poster's comment uspet you so much, and I do understand why.
However, the poster was responding to a PP who was saying that people earning below a certain amount are not contributing. So in context, if we are talking about things in these purely financial terms, and saying that lower income people are not contributing, then people on benefits are not contributing either! Personally I don't believe people "are what they earn", and agree with your points, but the poster you're responding to was talking in that purely financial sense in response to the PP disregrarding workers on lower tax bands.
I found the PP's comments upsetting, as someone who usually works (although job hunting atm) but in low paid roles. I've tried so hard to get back to work after a long time unwell. I have a disability that restricts my earning potential (but doesn't qualify for PIP, and there are no other benefits I could use to top up my reduced income). I don't think not being a net contributor makes me worthless or that I shouldn't be allowed an opinion. I also take issue with the idea that I should just get a better job/work more/it's easy to earn more, because it really isn't that simple, and it's the same for so many.
This is a serious point, and ties in with what another poster said about "levelling the playing field with who?" If people are having to tighten their belts, perhaps they realise they can't afford a holiday or even are having to budget every single penny, you can see how it could seem unfair that a disabled person they know could afford a holiday. In the context of worsening standard of living for everyone, it doesn't help to just say, as the PP did, that they should all just get a better job.
Plus, many disabled people (who are able to) are working, and many of those have reduced earning potential due to their disability but no financial support with that. If the government want more disabled people working, and are successful in achieving that, then this group will be even larger. Focusing only on "the most disabled" makes the situation worse, where you qualify for sufficient support, or none at all and live in poverty due to disabilty affecting earning potential. Tying UC conditions and top-ups to PIP makes this even worse, especially as "most disabled" appears to be a code for "physically disabled" - someone who uses a wheelchair may need PIP for mobility (quite rightly) but be perfectly able to work in an office job, whilst someone with MH issues may not qualify for PIP under the new rules (and therefore not the disability element of UC) but still not be able to work, consigning them to absolute poverty and making their mental health worse.
I don't agree with what the government are doing, and lived through it before as I was at my most unwell (on ESA and DLA as it was then) when the Tories made big changes last time. But I can see why people might have concerns about the current system, and that it doesn't help to have this black-and-white view of who's deserving of support and who isn't, rather than a more graded approach. Changing the system is fine, but the way they are going about it will make things worse in a variety of ways.