I'm not sure if you're being sarcastic, but yes, people should have access to computers in prison. Unlike in USA, many other countries do actually try to get prisoners back to being normal, productive people instead of just punishing them. Now, internet access and such is another point because that could be used to communicate with other criminals outside.
Actually, you might be surprised. Some prisons do provide web and email access, albeit extremely filtered, logged, etc. The issue at hand is that the vast majority of work-place jobs require some interaction with a keyboard and screen, and that without adequate experience with computers then ex-offenders' job prospects include only labouring work and similar. The cost of recidivism is far higher than the cost of rehabilitation (assuming the offender wants to be rehabilitated, of course).