Thanks for the responses - it's much clearer now.
I thought I read specifically that oral desensitization therapy was not made available to adults because kids are expected to "outgrow" allergies and will respond to the treatment, but adults would not respond because their allergies were typically lifelong. That was a few years ago, though, and I have not even thought about allergy treatments since, since strict avoidance has worked OK for me. I only go to a very, very few restaurants, don't eat other people's homes, don't go to new restaurants, etc. I never had to use my Epi-Pen since my reactions always passed quickly (even the time my throat completely closed off, it lasted just a very small amount of time) and I was doing pretty good. Since getting very strict, I'd been incident-free for about 18 months and even starting to think I was getting less sensitive to cross-contamination. For my specific allergens, I had anaphylactic reactions about five years ago to shellfish and milk within six months of each other. My primary doctor handed me a prescription for epinephrine and told me to find a youtube video at home to figure out how to use it and that I did not need to see an allergist since they "can't do anything". I went and saw an allergist anyway since I had a PPO and did not need a referral and I wanted more information, at the very least a lesson in using the Epi. He started out by assuring me it was 100% not possible for me to have adult onset food allergies and sent me for an expensive test for some genetic disorder he was convinced might be the source of the throat-tightening. I ended up passing the skin prick tests but failing the blood test for shellfish. That caused a lot of panic on their part because they told me the blood test categorically cannot be positive if the skin test is negative. I think they may have actually told me I could go ahead and eat anything I wanted so they got very stressed out trying to reach me to let me know. I never had any definitive diagnosis for dairy, but my symptoms were the same so I avoid as strictly. The allergist wanted me to do an oral food challenge for milk in his office (nowhere near an ER) to confirm milk, but I declined that on the advice of an immunologist I know who thought it was suicidal (he also did not have kind things to say about allergists). I have not seen an allergist since. Fast forward to this month when I developed a serious reaction to almonds - much more serious than any previous episode - and ended up with my husband using the Epi on me and me landing at the ER for observation (they were great). When I followed up with my primary practice, I was advised to get tested again for any new allergies and referred to this allergy practice.
I think with the "shots" that it was the primary doctor who was just confused about what was available or maybe I seemed like I might not comply in seeing an allergist (I told her about the bad experience last time) and she wanted to convince me they have things they can actually do to help and she told a little white lie. She sent me to an allergist associated with a large research hospital, so I doubt that this person is doing anything like what you are describing, lakeswimr (University of Pennsylvania). I thought maybe things had progressed a bit in therapy and I missed it. I would be too nervous to do desensitization therapy even if they offer it, I think, just like the oral food challenge gave me the heebeejeebees.