Agree with assessment.
1. If you get a chance, rotate through a small community hospital, a large community hospital, and a large academic (university) hospital - not only is the exposure to pathology different, but so is the culture (for better or worse). I think AOA vs ACGME is a red herring - for fields like internal medicine, doing it at a small community hospital vs a large academic hospital will be different. Sure, the "material" will be the same, as well as knowledge expectation - but small community hospitals ship patients to large academic hospitals. The bread-and-butter cases you'll see everywhere - but the more specialized stuff as well as exposure to advances in medicine (bone marrow transplant service, solid organ transplant service, IABP/LVAD/ECMO, etc) help form a more complete physician. An AOA residency at a large hospital (with those services) will provide a more thorough education than an ACGME residency at a small community hospital. Unfortunately a lot of AOA residencies are located at small community hospitals and hence the perception of inferior AOA residencies.
2. Unlike premeds, the public actually don't care for academic pedigree, and there is actual disdain for academic pedigree (why do you think politicians bash their ivy league educated opponents during debates and commercials about their schools, and why do the opponents hide their pedigree?). Only a small percentage of patients will seek out pedigree (e.g., I only want a HMS alumnus, Hopkins residency trained, Cleveland Clinic cardiology fellowship trained, full professor of medicine/cardiology at Mayo Clinic, and holds the MACP designation in addition to FACC, to treat my run-of-the-mill hyperlipidemia). In that case, you can't win (actually, if they don't come to you, trust me, it's a win on your end). On the other hand, how many people have a distrust for "modern medicine" and will turn to naturopaths, chiropractors, rekki practitioners, their grocery clerk who works part time at GNC, the ladies at the perfume counter at Macy's wearing a white coat, etc. Premeds are so obsessed with that "MD" title that they forget the rest of the world don't really hold it to the high alter that they do.
3. The discrimination/hurdle is at the residency, and perhaps fellowship level. It's there. Some places/fields are more prominent. Others not so much. There are some inherit bias against DOs (known vs unknown, since LCME schools are known to PDs, while DO schools, which are popping up like weeds, are unknown), unfamiliarity with COMLEX scores (is a 600 a good score? what about a 700?), inconsistent clinical exposure (all outpatient rotations during 3rd year medical school, having a nurse as surgical preceptors, etc. Some schools are on the ball and have excellent clinical exposure with good affiliation, while others throw you to the wolves). But once you make it pass that hurdle - it really doesn't matter. Once you get in, no one cares if you're a DO or MD. They care if you are a good doctor or not. In private practice, if you can be a good employee/partner and generate revenue (while making the lives of other doctors easier), they don't care about your degree. In academic medicine, there's more academic "snobbery" involved, but they care more about your scholarly activities, ability to bring in grant money, and reputation amongst your scholarly colleagues. There are academic DOs at UCSF (Robert Hendren is a professor and vice-chair of psychiatry), Harvard (Ross Zafonte is an endowed full professor and chairman of PM&R at HMS), Yale (Michael Leslie is an assistant professor of Orthopedics and Rehab), etc. Of course it is a tougher glass ceiling to break, but it is possible.
4. Your stereotypical pre-allo post would be "Help, I'm a 4th year college student with a cGPA of 2.3 and sGPA of 2.1. What can I do to become a doctor, and I don't want to be a DO unless that is the last and only option. Btw, please read my personal statement on how I want to be a doctor because I want to help people". But of course, the pre-osteo post would be "Help, I'm a 4th year college student with a cGPA of 2.3, and a sGPA of 2.1. I just discovered osteopathic medicine and fell in love with its philosophy, its history, and the DOs I will soon meet are nice and friendly, unlike the MD jerks. Quick question since I don't have any google or wikipedia skills - can DOs write prescriptions? Also I want to do dermatology or radiation oncology residency at Harvard Medical School, but I'm afraid the DO degree will stop me (it's gotta be the DO degree, what else could prevent me from that residency). Is that true?" You can't help but laugh sometimes.
Just do your best, whether in undergrad, medical school, residency, fellowship, post-fellowship (eg real job). Live life. Make people better. Make people smile. Do that, and no one will care if you have MD or DO after your name.