They were already doing that by putting ads on their videos. It's not as explicit as just outright asking for money, but it serves the same purpose. It all really comes down to if you believe their time, effort, opinions and personality compensate for talking over content that isn't owned by them. And if you decide what they are doing is wrong you also have to keep in mind that that same criteria will include many more people than just them. Like every partnered game, movie and tv show reviewer and let's player. If so, that's your prerogative. But not everyone agrees. Or cares.