Remember too that people don't post when everything goes well, just when it doesn't so that makes it seem more common than it actually is.Yes it is unfortunate because it seems like more and more people who order female chicks or buy what are supposed to be female chicks at feed stores end up with some cockerels just when sexing is more important than ever with people now raising layers in cities and suburbs. I am glad you did well but from the amount of sexing posts in here it seems like lots of people get unexpected surprises. I think it's very important to let whoever sold the chicks know when cockerels show up in what was supposed to be pullets. Communication and even complaints are the only way I see the situation improving.
IMO, if people live where they absolutely can't have roosters and they have no plan for an oops cockerel, they should buy hatchery bred sexlinks.