Because many people are in prison for non-violent offences. The companies which make money from prisons, and the unions along side them, put pressure on the police to ensure people are sent there, as it is in their financial interests. Hell, the police like doing it because it makes them seem "tough on crime", without having to explain the difference between someone having some weed or stabbing a nun in the face - "crime" is "crime", and the tougher they are on it the better for them.
If the people in prison were there for good reason, then you'd have a point. As it is a sizeable portion are there for absolutely no good reason, and the system actively encourages that.
Your understanding of this field is flawed, it seems. The "mild warming" you are talking about does not improve agriculture. The crops humans rely on are heavily suited to their environment. Our staple grains are usually less nutritional with increased CO2, so we'd need to grow more to sustain the current population. The land suitable for agriculture will move towards the poles, into areas with sub-par soil (in the case of areas previously scoured by glacial activity) and no infrastructure to farm it (as the farmers live where they currently farm, and moving them, their machinery, and the associated industry support continually towards the poles for generations to come). So not only are your grains less nutritional, you need to grow more of them with fewer resources in poorer soil.
People do care and they have called out the charlatans. You seem to believe the charlatans, though, which would explain why you are claiming things the evidence simply does not suggest. I'd suggest reading the IPCC reports, but I don't think that'd help you.
If all else fails, lower your standards.