Being an "ex-con" myself...
Well... I dont post much however here's my to yuan.
This is not really true. I grew up in the ghetto and sadly due to a bad lawyer I went to prison for a year for protecting the pregnant mother of my child with a crow bar and a box cutter.
99% of the people I knew in the ghettos only put on gloves and did boxing training to the body only. It was kind of like a ghetto past time.
IME 99% of the hand to hand fights/attacks I have been in they are powder puff punchers.
The worst part of prison was not the riot I was in but having to stay in a small room for 2 weeks straight with 2 other men as punishment for it.
This is pretty untrue IME. There is 1% in hand to hand who are viscous and very kamikaze styled (I myself had to be this way and never "put on the gloves" and instead used viscousness and weapons due to my size). Now I study IMA due to disability.
Guns weren't a thing where I was because the laws were tight (although I had a close one in high school as a by-standard). In other cities where it is very easy and cheap to get guns that is usually what is used so when they go to jail the only the to fear is size after lifting trash bags full of water for a year straight. However there is everything from a hot pot to a sharpened/broken toothbrush to take care of that. I have to say if there is any jail based hand to hand style is it to "put on the gloves" on go for body shots IME.
Now luckily I am a software engineer going on 11 years doing so and a 8 year old daughter and a 4 year old son (they practice XMA). Unluckily I am disabled now due to chronic pain and have to live on Morphine. However my children keep me going at it in work and work-outs.
Hope this helps and did not stray too off topic. Regards!