Only in consumer video game fandom would there even be a debate about whether or not content "should be" political.
We don't have that conversation about books, film, television or music, since everything is, whether it wants to be or not, 'about' something. The version of reality you present in the fiction you create necessarily says something about the world, or how you see it.
Most smart people know that even "leaving politics out," where it's possible, is a political decision in itself. But that doesn't stop some influential YouTube personalities from making weird statements like these.
Fiction and fantasy are one of the ways we achieve distance on the issues of the real world -- sometimes through escaping it entirely, just for fun. But throughout history storytelling has also been a way for populations to share culture, express morals, or otherwise record their values, and many of the last century's most popular media empires are about conflict among peoples in epic land and space wars. Elves, trolls and aliens are how we process and provoke discussion about "otherness" on our own planet.
Today, Call of Duty and Grand Theft Auto are among the most financially successful brands in games -- one of them lavishes on wars abroad, the other at least tries, in its way, to satirize American moral panic and consumerism. When arms manufacturers have direct relationships with games themed around the U.S. military -- and they do -- it's much too late to say there's no room for politics in fiction.
It's not that one can assign "politics" or the absence thereof to individual works so easily. What, for example, are the politics of I Am Bread (gluten agenda)? It's not like you're a bad person if sometimes you just want to tune out and have fun. Admittedly, those games about shooting all the foreigners are really good fun so long as nobody reminds you to think about the real world. But exhortations to "keep politics out" of games are just more ignorant bleating against a tide that's inevitably leading games to mean more things to more people.
At Kotaku UK, my friend Keza MacDonald has a great, readable essay you can send to anyone who tries that bleating at you. Bookmark it for frequent use?