Now this was a mistake I should not have done…
About a month ago I have moved my AWS EC2 machine from Amazon Linux to RHEL 6.2. This was good. I have moved all my files and stuff, recreated my own user, everything was just fine. Then I copied my gitosis account (user git and its home directory). Then I tried to log in. It failed. I was blaming OpenSSH for a week or so, changed the config file in several ways, tried to change the permissions on ~git/.ssh/*, but still nothing. Permission were denied, I was unable to push any of my development changes. Now after a long time of trying, I coincidently tail -f-ed /var/log/audit/audit.log (wanted to open auth.log instead) and that was my first good point. It told me that sshd was unable to read ~git/.ssh/authorized_keys, which gave me the idea to run restorecon on /home/git. It solved the problem.
All hail SELinux and RBAC!