I don't think so no. They decide themselves what to put into their video. It's important to remember that the video we see is just a video showcasing what they feel like saying in the video. If they think that complaining about things lacking in the game does not make for a good video then they are probably not gonna do it.
Some might show how they feel more often than not, often youtubers have a specific style they tend to follow which works for them so as for the youtuber that you mentioned the impression I have gotten is that she is sometimes very positive and sometimes also very negative about some things.
She likes to say "This is the worst day of my life". And that's part of her style and that's also what makes her videos fun to watch.
