I know it's just more anecdotal evidence....but my mother was signed off sick by a doctor and what you've heard on this thread is only half of it....
Whole other system for people who are sick - ESA - but they try to get you off ESA (on which you don't have to look for work seeing as you are too ill to work) on to JSA (to make you look for work you're too ill to do) by doing a bullshit 'assessment' that does not take your doctor's medical evidence into account. The questions are ridiculous and don't really test someone's fitness for work. As a result, more than half of those told they are fit to work who appeal that decision are found not to be fit to work when medical evidence is taken into account. The point of the whole thing is just to make it really difficult to get benefits for disability.
My mother was one of the ones who was told to work, then appealed, and got told she was too ill to work on appeal. However, she did not get put on the 'disability group', she got put on WRAG (Work-related activity group).
WRAG is the most kafkaesque policy our government has managed to push through. If you are on WRAG, it means you are definitely too ill to work - the state agrees, the doctor agrees - but in order to receive your benefits you have to work. For free. Either volunteering or for a private business. So not only do you still have to work, you don't get paid for it either.
Anyway, how much benefit you get depends on your savings. When my mother first got ill she moved to be closer to her family (who would help her out when ill) and was housed by the council in an unfurnished flat. She did not own furniture of her own as she had previously lived in a furnished flat so she bought cheap furniture from auction/Ebay. She also gained weight on her new medication (side effects are weight gain) and had to buy a whole new wardrobe of clothes in a the size above. Again, she used Ebay and charity shops to buy these clothes thinking she could not afford to buy from the high street.
For this, she was sanctioned. She had to present her bank statements now and again to show she wasn't scamming the system and they saw all these little payments coming out on Ebay etc. and accused her of 'frittering away' her money in order that she fall below the threshold for full benefits. Her benefits were thus completely stopped and she had zero income.
It took her months to get her benefits back and to appeal for backpay of what she had lost because she had to 'prove her case'. Those months were spent speaking to people in call centres who told her "the decision maker" would be the person who would decide if she received an income. She was not allowed to speak to "the decision maker", nor know their name, nor know where they worked or what their role was. She had actually complied the evidence to show she spent her money on essentials - it took her fucking ages - but every time she sent it to them there was 'something wrong'. The fax didn't come through/we didn't receive that email/you can't send things by post because it all gets rerouted through the distribution centre blah blah blah.
If you give people targets for how many 'sanctions' they have to give out they will just find reasons and then they'll make it really hard for people to appeal.
The whole thing is completely absurd and designed specifically to make it very difficult for the genuinely vulnerable to get help.