Hey bud, here's a redpill for you:
The state recognizes that a percentage of the population is economically unviable, meaning their only function as individuals is consumption. Realizing this, it is actually more cost effective to simply bribe these people with SSI payments, the alternative being riots and blood in the streets. Money equals complacency.
Maybe you're entitled to your rage. Afterall, SSI is literally "wealth redistribution" as SSI funding comes from income tax revenue. Surely people who actually work for a living, especially those at jobs they hate, with little to no benefits, should be pissed when the sense of pride they derived from their self reliance is undermined by those who basically get to game the system and reach the same ends? What makes them better than me? As far the state is concerned, nothing. Move along citizen.
The reason SSI is initially allocated by doctors, and the medical industrial complex, is because socialism is (officially) politically untenable in the US at this time, and the idea of SSI being under the jurisdiction of the government would never be accepted by the workers. But if sublimate everything into "medical issues", many of which are completely made up, i.e. basically all of them, we can continue the charade that is Western society and go another day without our cities catching fire.
Let's face it, automation in the work place will eventually make everyone unemployed, so SSI is a decent stop-gap between Dickens and Marx until UBI gets implemented. At the end of the day, we're all going to be government employees, user...
tl;dr: SSI is basically Universal Basic Income and wealth redistribution wrapped up in medical jargon to make the bitter pill easier for workers to swallow.
That being said, how the fuck do I get in on this SSI action? UBI is probably two presidential terms away at least, and I don't want to wait until the cusp of the technological singularity to enjoy the perma-NEET life.