Are posters trying to say that not having had sexual intercourse is a material reality and that virginity is a social construct connected to that reality?
Something like that yes. Historically, virginity has been placed on a pedestal and all sorts of personal qualities have been attributed to being a virgin - being “good”, pure, somehow more worthy of respect, innocent, unaware, unawakened, with no libido etc. Sometimes the qualities associated with “virginity” are supernatural and other wordly, “angelic” etc. Virgins of the female sort have been seen as having more worth than women who have had intercourse, even if it was without consent - a very damaging narrative. Male virgins however are seen as inferior to other men...you don’t become a “man” until you have penetrated a woman.
The material reality as you put it is that one has either had sex for the first time or not. That’s it. No superhuman or freakish qualities, no weird beliefs about value etc.
Take this phrase - “He took my virginity”...what does that mean? In real terms “that man was the first person to put his penis in my vagina”. But he’s not actually taken anything has he? He doesn’t have ownership of something. The person hasn’t just been transformed into a totally different person. Their inherent value hasn’t changed.
And then there are all the other issues around lesbian sex, anal, other sexual activity. Is it just the breaking of a hymen that counts as losing virginity in a woman? Because in that case Frida Kahlo “lost” hers when she was in a bus crash during which she was impaled as a young girl. I would have “lost” mine age 8 during a pelvic examination. So in that case what was the first time I had sex?
Are exclusively lesbian women virgins until they die? I’d say no!