It is somewhat of an oversimplification to call Lizzie Magie an "anti-capitalist", and I certainly think she would object to Jamie's assertion that she made her game un-fun on purpose. It's actually a pretty neat story, and if you aren't already familiar with Magie, I highly recommend reading about her life's work.
I do believe that all art - even something as simple as a comic strip or a game or a six-second video - can carry both explicit and implicit messages, and we as creators have a responsibility to think critically about the messages we send.
Imagine I've created a little free-to-play app where you mine gems from the ground. The game scales up as you progress: more gems = bigger drills = deeper holes, etc, and it continues forever.
That app would carry with it a number of implied statements... morals-of-the-story, if you will. It sends the message that labour is always rewarded with both immediate rewards and the potential for advancement. It sends the message that bigger and shinier is better. It sends the message that industry - in particular, the harvesting of natural resources - can simply continue generating greater and greater profits indefinitely. It sends the message that a jewel in the ground is immediately the undisputed property of whoever digs it up first. It sends the message that no one will help you - that no one is helping you - and whatever you make is therefore entirely yours. It sends the message that working to make money is the only meaningful thing to do with your time.
I might not intend to send any of those messages with my app, but they're in there.
Now, imagine that some six-year-old with a pliable brain gets a copy of my app and plays it for hours and hours every day, as six-year-olds are wont to do. Who's to say how I'm molding that child's character, how I'm shaping their subconscious? Would the lessons be different if I included a poor family you had to make money to feed? Would they be different if the earth only contained a finite, irreplaceable number of jewels? What about if you start the game with a Tom-Nook-like figure who lends you your first drill, and thereafter takes every penny you earn to pay off the interest on your debt to the Company Store?
And y'know what? That explict and implicit messages thing can apply to every form of communication, no matter how incidental. Take the shirt Jamie's wearing, there. What implied messages about the nature of butt-touches does it send?