I quoted the beginning because your comment was long. I was also talking about backhanded compliments. Just because you insulted him doesn't mean you still didn't compliment him. Someone asked for an example and I gave them one.
And for me selling out usually means endorsing a product you don't believe in. You describe Arin as not being passionate about Game Grumps but to me he seems to still enjoy playing games so Game Grumps is still enjoyable to him. He hasn't changed that much since Jon Era so I do believe he still enjoys playing games for a living, wouldn't you?
But let's scrub the pixie dust off your glasses for a sec and look at this from a purely objective standpoint. Arin likes games, playing games makes money for him, he needs money to continue doing the things he likes, he makes money for doing something he likes. Since when is that selling out? Too me, way too many people think streamers and let's players are sellouts. They aren't, they do something and they get paid. People seem to think the more money you make, the more of a sellout you are. I guarantee you if the Game Grumps didn't make as much money as they do, people would not call him a sell out as often as they do.
Now let's continue using those pixie dust free glasses and look at every person who has a job ever. Most of them don't enjoy their work, they do it because they need the money to do things they like. Now what on earth does that remind me of? Could it be the Game Grumps who do their 'work' in order to do things they like? Let's be honest here, animation does not put food on the table for Arin anymore but that doesn't mean he has abandoned it or anything else he likes. He still animates and is currently working on a longform series and he is helping Ross write (another thing he clearly enjoys) Gameoverse. Do you think he would be able to do any of this if he didn't have money? The answer is simply no. By your logic you must chastise anyone with a day job.
Now, let's place you in Arin's shoes. You don't have a degree. The one thing you used to do to pay the bills can no longer do that unless you spend every waking minute doing freelance work (if you can find it). But you get to play video games every week and it gives you more than enough to be happy and focus on the things you want to work on without worrying about paying rent. Through this weekly job, you have provided a job and more exposure for a once struggling musician. You have also provided a padded landing for an Australian immigrant who also cannot pay the bills with animated shorts anymore. You have also kept a job going for a person (Barry) who was struggling to even support himself until he started editing for Game Grumps. And finally you get to work with your favourite friends and the woman you love every day surrounded by things you like in your own comfortable office. Would you quit the one thing that provides for you and all of these people?
People like you are the type to chastise someone who drives a Lamborghini. It's not like Arin fucking stole the money he has, he earns it. Just because you don't like what he puts out and you feel he is a sell-out, doesn't make it so. He makes money because people watch and people watch because they clearly like it. In the words of Burnie Burns of RoosterTeeth, if people watch it, we'll keep making it. That's not selling out.