"Lounge Dragon" in this context means the lounge attendant, aka. the gate keeper between you and the lounge. The word "Dragon" is used to denote a connotation the said person can be at times argumentative, obstinate or otherwise, somewhat unfriendly or even unprofessional usually due to a disagreement with respect to lounge access policy.

Oneworld policy is crystal clear per what's written. Unfortunately, the job of these lounge attendants are often part-time jobs with high turnover given that some of these overseas lounges are only opened for a few hours a day. I read up a little more in the Oneworld forum re: SFO airport. Another poster reported while flying LAN and being a Oneworld Sapphire, he was turned away by the BA lounge dragaon in SFO but welcome in by CX. The BA agent told him that if she let him in, LA won't pay for the access (that is 100% false). What's incomprehensible about that case is not only she had no idea what she was talking about, on the Oneworld website, it clearly stated that LA passengers are to be directed to the BA lounge in SFO. How did that happen, nobody knows. It goes to show you can't expect too much from part-time worker who may or may not be well trained. There was even another case of a TAM Business Lounge in GRU specifically denying access to Oneworld Sapphire, in direct violation of Oneworld policy.

Those are issues that need to be brought to the attention of those who need to know. But if people don't report them, nothing will be done about it.