O Apache sempre começa como root nos derivados do RHEL (como o CentOS). Em seguida, ele usa o setuid para alternar para o usuário / grupo configurado no httpd.conf.
Em mod_wsgi docs :
Note that having denoted that daemon processes should be created by using the WSGIDaemonProcess directive, the WSGIProcessGroup directive still needs to be used to delegate specific WSGI applications to execute within those daemon processes.
Also note that the name of the daemon process group must be unique for the whole server. That is, it is not possible to use the same daemon process group name in different virtual hosts.
Options which can be supplied to the WSGIDaemonProcess directive are:
user=name | user=#uid