I doubt in each of these cases people are making the rational choice to ditch the meds in favor of a state of "pure madness". Instead they probably get fed up with side effects, and decide that "this time won't be as bad", or "I'll just stop taking them for a day".
I had to learn to be a different person. (Discussed in another comment.)
This is an extreme example, but imagine smashing into an artist’s home, breaking their tools, and telling them they’ll be working in a warehouse for the rest of their life.
Maybe they’ll be happier working in a warehouse, but they don’t know that. Change is hard.
It’s not as simple as they didn’t like the drugs.
I’m fortunate to have kept my creativity. If I had lost that, I’d prefer being crazy, even knowing it would end badly.
Lots of people voluntarily take substances that make them think much less clearly but also make them feel good: it's just a matter of scale
I've known three people one directly and two indirectly that were lunatic level if they were off meds and all refused meds consistantly.
1. Was a guy I worked in the same dept during an early job. His thing was to start telling people that government agents were in the elevator to control your mind or something and ending out emails about it and corning people to warn them. Funny thing was it was a government job so there were government agents in the elevator pretty much anytime someone was in the elevator. He resisted because he didn't like the meds.
2. My friends brother in his 30's would not take his meds and his parents had to sneak them in his food. If he missed enough doses he would eventually go raving mad into the woods and eventually be found passed out somewhere by emergency responders usually naked and injured. He resisted because he didn't like the meds.
3. My brother in laws brother was paralyzed and brain damaged from a car wreck. Yet when off meds he would run off in his wheelchair into dangerous traffic or be found passed out(and injured) from exhaustion of crawling because he went somewhere a wheelchair couldn't go and just crawled for miles. Again he didn't like the drugs.