Old people do matter, but due to aging their risk of getting any disease increases. People are less concerned about them because old people dying is inevitable; they're old. Young people, not so much.
I only make fun of people who say not all men when people say that on a post about a personal experience. It's like if someone posted about their experience with false rape accusations and I said "not all women". No shit, it's not all people, but that wasn't the point of the post.
People who worry about a woman's sexual history are not worth my time and energy. I mean, I get it if you're worried about STDs. But if you're worried because you think more than one partner tears the labia or something, then stay away from me.