Passion is right. Strep is everywhere and some people are persistent carriers and can infect others or become ill themselves whenever their own immune system is compromised. As to the STD and daty or other contact, there are of course risks especially when you have an open wound, ulcer, etc. in your mouth (or anywhere on your body that contacts the pathogen) and that risk is also compounded when you're own immune system is weakened (sounds like yours is).
From a hobby perspective, pick your partners carefully. Don't play with a dirty kitty, and be very aware of your own health (if you have open wounds on your crotch, penis, fingers, or in your mouth) because the key to transmission is the fluid to blood/blood to blood breach.
Given your overall health factors/reduced immune system performance and your age bracket (I'm assuming it's significant based on your comments of longevity), I agree with you that it's probably unwise for you to hobby or partake in anything where the threat of bacterial or other viral pathogens are likely. You (specifically) should also take care when you are handling veggies, fruits, and of course raw meats. I would also suggest you get the flu shot annually, and consider adding the pneumonia and shingles shots. As added protection (given your history) you may also want to consider a meningitis vaccine (booster) as well.
And.....always wash your hands regularly (I admit I'm OCD about this).
Take care of yourself and your body will take care of you.
Best wishes