I'm another hobbyist who also happens to be an MD. I occasionally treat patients with STI's, though it is not my area of expertise. However, I agree that I found the OP somewhat confusing, and thought I'd try to clarify a few things.
Most of you seem to recognize that it is critical to separate viral from bacterial STI's, at least in regards to treatment. HPV, Hepatitis B, HIV, and herpes simplex are all viral illnesses, thus antibiotics are ineffective, though occasionally anti-viral meds may be beneficial. We have vaccines for HPV and Hepatitis B.
Gonorrhea and syphilis are caused by bacterial infections, and there are antibiotics that are effective against them ..However, as the OP says, there has been significant recent resistance,to gonorrhea,, which requires a change in the treatment regimen. Even though Chlamydia isn't a bacterial infection, there are actually antibiotics which are effective against this. Same with Trichomonas, it is a protozoa, but it does respond to meds.
Prevention is ALWAYS more effective than treatment, so we recommend vaccination when possible. Strongly consider HPV vaccine if you are not over 26 yrs old. Get a Hepatitis B vaccine, it is the only one of these required as a rule
for medical professionals.
And a huge piece of prevention is consideration of the relative risks of various sex acts, whether they be oral, vaginal, or anal. It's been discussed ad nauseum on many other threads, so I won't digress any further here.
As far as the comment of using some simple antibiotics after contact to protect against some of this, you have to know what you are treating to know which antibiotic to choose. And this isn't some country where antibiotics are available over the counter. As someone already said, if you think you need to treat, then you'd better start to run out of there.
I'm not from San Francisco, but I found this resource excellent for both lay and professional readers.
Www.sfcityclinic.org