I think what was quoted is not the same as claiming people that used something else as unprofessional.
Redhat certainly is very popular and in many ways it is a defacto standard that other 'enterprisy' distributions tries to emulate closely. Systems like Suse and Unbreakable Linux. This is done for application compatibility, of course. I don't know if this translates to a 'gold standard', but I don't think he meant that somebody using other things is inherently unprofessional.