There are no doctors currently posting on this site, but our answers are based on the advice of EXPERTS in the field of HIV. I have no idea why other doctors say something different, but there are plenty of doctors who aren't all that educated about HIV transmission, or who are overly cautious.
Drs. Hook and Handsfield, who used to post in these forums, have many, many years of experience as HIV specialists. They do not recommend testing or concern after an oral event, so we do not either.