Dude, no one would care if she was a virgin or not if it was written correctly, but no, she was written as the pure MC's childhood friend who never even kissed him, who was always in love with him, was shy and withdrawn, but suddenly boom, she wasn't that and was just the MC's friend who had sex with random guys even though she said she liked the MC, which is completely contradictory to how she was presented, if that was made clear from the beginning it wouldn't be a problem, but that's not how it happened, so you can't be upset with people complaining, unless you don't care that the story doesn't make sense.