The bartender was correct regarding the Mai Tai. While she may not have been familiar with the Tambu Lounge (I don't think any of them except Christian have been to WDW much, if at all; Christian, on the other hand, did the college program and worked at EPCOT. He'll know what you're talking about), the HippopotoMai-Tai is very close to the Trader Vic's original mai tai recipe (only difference is Trader Vic's recipe calls for simple syrup as the sweetener, while all Disney bars use agave nectar. The taste difference is negligible).
I've worked Tambu a couple of times when statused at the Barefoot Pool Bar, and I was never aware of a mai tai unique to the bar besides the Captain's Mai Tai found in the generic Disney drinks menu. There was a time when Tambu carried special ingredients for authentic tiki drinks, such as coconut cream and orgeat, but that was quite a while ago. If the mai tai you like at Tambu is the Captain's Mai Tai, the Trader Sam's bartenders can make it, as well as any other drinks in the generic menu. Often, if you just ask for a mai tai, they will ask if you want the HippopotoMai-Tai or the Captain's Mai Tai.
As for the bartender, it sounds like you met Rhonda and her sarcasm. She plays it up as part of the Jungle-Cruise-skipper-turned-bartender role, and I am sure she only meant to try and enhance your experience. I cannot speak for her, but I have never seen any of the bartenders, Rhonda included, treat anyone rudely. Rhonda and many of the other Sam's bartenders have been bartending at the
Disneyland Hotel for many, many years (a few of them have been there for over 20 years!). They are old-school, pre-Pressler Disneyland cast members. Again, I cannot speak for them, but this report does not at all correspond with my weekly trips to Trader Sam's. Sorry you had a bad experience; give them another chance sometime and let them take good care of you!
Incidentally, did you try the HippopotoMai-Tai? It's really good. I've seen a few questions on these boards about whether Trader Sam's can make Tambu drinks or other WDW-specific drinks. Why not try a Trader Sam's drink and have an original Disneyland experience?