I agree privacy and being ashemed are two different things.
You can behave with a certain amount of discretion.
You do not have to demonstrate what you are doing.
Quote:I thought of different taboos in our society such as breastfeeding in public, menstruation, mental illness, being alone, nudity, acne and more.
Breastfeeding can be done in a demonstrative way, which is uncomfortable for people around the mother and child.
Of course women talk about menstruation around other women. But it certainly is not something which fits as a dinner conversation just as little as problems with other more intimate things.
Of course one can talk about mental illness, but again please in a nice way.
What you have mentioned are things which most of us do not want to see, hear nor talk about if it is not with a very close friend.