When gaming started out it was not really defined as male or female past time. Sure the original Space Wars! were created by all male team, but games like Pong and Pac Man were as popular with female audience (and more for Pac Man) as with male. Somewhere, along the way the industry shifted gears and games became more and more geared for male audience, at the same time society pushed the idea that video games were not for girls.
This shift could be the result of the video game crush in the 1980s. Major toy companies lost interest in the video games for a while, and so it was left to the the enthusiasts to keep the light going. For example, in Britain, they were coding the games for the personal computers based on the magazines that published the lines of codes. This might have been the period where the gaming started to be something boys did, because it was seen as something to do with electrical engineering and technology. The general attitude at the time was that engineering and mechanical fields were for boys and not something girls did. So when the video game industry started to comeback with Nintendo and other companies, it became male focused.
At that period there was a strong perception that girls played only adventure games (like Myst), hidden objects games, or casual games (like match 3). Boys were the ones who everyone saw as playing actual big AAA games in FPS genre, 3rd person shooters, RTS, Grand Strategy. Now that was not 100% true, my brother had a friend in high school that played Unreal Tournament, and she could wipe the floor with any boy from school in that game. But overall the perception was that you want to get a game for girls get Barbie’s horse adventure, you want to get a game for a boy get that one that is advertised in front of GameStop on a standee that features a space marine dual wielding pistols.
As the industry continued to marching forward and competitive side evolved, that too became naturally dominated by those that played the videos games most: boys. We still don’t have too many female e-sport players. Now, again it is not to say that girl gamer did not exist, because where did Felicia Day, Brooke “Dodger” Thorne, Rossanna “Ro” Pansino, and others came from. But overall the perception was built this if boys only past time.
The standard media’s perception of the girl gamer was born out of what they saw in video game media. While, the early video games had been limited by graphics the later ones had fewer issues there in adding sex appeal to the games. Breath of Fire had female characters, but they were pixelated, Laura Craft in the first Tomb Raider game had already her (Ph)-double-Ds but they were 2 triangles (well pyramids technically), Heroes of Might and Magic 3 had a female protagonist but in cinematics she had no curves, Kerrigan in StarCraft did not have enough resolution to make out any details. But as graphics evolved we got well curved Samus in blue spandex, curvy Miranda Lawson and of course the female armor in games. I remember there was picture, I think from ArcheAge, where the female characters showed less skin when wearing armor, rather than when wearing it. It was clear that the game industry was going for sex appeal to teenage boys, even when a cover for Spellforce, an RTS, had a female in skimpy dressed showing ass and breasts off at the same time.
So the media went looking to see what kind of females would be found in this past time given the female imagery in the games. The rise of Twitch (before Just Chatting was created) provided them with the answer. There they saw a lot of channels with “girl gamers” who were sitting there in low cut tops with camera pointing at their breasts, saying something along the lines: Oh I don’t know anything about video games, but I am sure you guys will help me, and please also donate and subscribe. So that gave the image that girls that were playing video games were not there for video games but to take advantage of horny teenage boys.
After all of that, of course, when girl gamer community started asking for change in representation of the female characters in the video games, the response was hardly surprising.