Yes, people are aware that cancer exists, but a lot of people aren't aware of the fine details. That young people get cancer, that certain types of cancer are influenced by behavior or diet, that men get breast cancer, that there are steps to take to make sure that cancer gets detected early, that there are multiple treatment options, etc., etc. This isn't just a matter of "Are women objectified in games?" but "How are women objectified in games? Just how prevalent is it? How does it happen? Why does it happen? Is anything happening to change that?" The videos produced by Feminist Frequency, thus far, are far from a complete and balanced view on the issue, but there have also only been two parts of one subject released. They might get better, they might get worse, but the fact of the matter is that the issue does need discussion. You make take for granted that "everyone knows women are objectified in games", but I'm betting most people aren't aware of the specifics, or the broad range of ways in which it happens.
I don't understand this argument. How does claiming "that's just the way it used to be" in any way invalidate showing how the history of the trope continues to modern day? She's not just citing games from the 80's, she's got examples from throughout history, including modern day. How does saying "it's a Japanese thing" make it have any less of an impact on world culture? (Especially since Americans made some of these games.) Yes, a lot of these games came about because of Japanese culture, but they were then exported to other markets, to have a cultural impact there, independent of the culture of origin.