I am a straight, fit, married with children forty-something. I cycle and run regularly and many times wear tights while doing so. Not girlie ones...Nike/Under Armour and always black. They are incredibly comfortable! They breathe and move with me unlike jeans or chinos/slacks...no bunching or need for constant adjustment. So here is the question...what is wrong with wearing them outside of physical activity? Given that it is done so tastefully and nothing is on display.
because no one wants to see the crevices of your nutsack? LOL you're not working out so it doesn't look right for you to be wearing work out clothes, sorry. if your clothes are constantly bunching and need adjustment, your clothes probably don't fit.
There is something wrong with it if by "outside of physical activity" you mean, for example, wearing your tights to go to the bank to deposit a check; wearing your tights to to meet your financial advisor; wearing your tights to pick up your kids from school.
Listen just because something is comfortable does not make it appropriate. Yes, there should be some objectives for appropriate. I may be comfortable in my pajamas but that does not mean I should wear them to a business meeting. In fact I am probably most comfortable in the nude. Does not mean I should sit with my friends at lunch in my birthday suit.
I know girls are starting to wear yoga pants everywhere now. Like even to bars. They do look great on. I have to admit that and that makes it harder for me to dislike it. But the principle takes precedence. No yoga pants outside yoga either!
I have this pair of long underwear (legs and groin only, not full body), that are kind of like tights. They're fairly form fitting, but the point of them is to insulate and keep water off. I wear them if it's really cold out or when I work outside for extended periods of time. I don't see anything wrong with it if it's for practicality sake and not for the look of it.