Like we expect a reviewer to base their review of a game on having played through it, people expect her to base her claims in this video series on having actually played through the games she uses as examples. It would show that she saw all of the game's elements (story, visual scenes, character types, etc.), read through the manuals (which often contain more story elements... especially with older games), and experienced it all for herself to get the full context of the game's events. This would give a greater understanding of the trope example within the game, as it would show if it's an incidental one that doesn't represent the game and its content as a whole, or a truly toxic one that the whole game runs with. It would give her arguments via examples a better sense of being informed, because she'd know if any parts of the rest of the game she's using contradict her statements. So in that sense, it is important, and does matter... especially with a touchy and volatile subject like this.
Now, I don't know if she pulled a cliff notes on her games, played through them all, or did a bit of both. As such, I'm not going to defend or accuse her, because that wouldn't be fair. That said, "Did she actually play those games completely?" isn't an unfair question to ask at the moment, given what's been shown, and what it potentially alludes to (namely, her possibly cherry-picking only what works for her argument, without ever actually playing the game to get its full scope and context).