Not just territory, but social stratification and ingroup-outgroup dynamics are present in nearly every social species of animal. Some are more strict and/or violent about it, but everything from fish to birds to other primate species have social hierarchies, a concept of territory, and a willingness to fight over both. Great apes have been documented conducting violent wars with other troupes over territory and resources.

I have to say that I've always found the argument that "X is an tool of control by the rich!" to be reductive. The implicit (or sometimes explicit) corollary is that "X" is therefore arbitrary, artificial, and bad, whereas I tend to think that usually inverts cause and effect. "X," whether it's social hierarchies, the concept of property ownership, or in this case territorial boundaries, are more often than not rooted in some innate social instinct that can often be found not just in people but throughout the animal kingdom. The powers-that-be may well be manipulating those behaviors to their benefit, but that doesn't mean that the solution is to deny that they are innate and claim that we can make a better society if we could only ignore them hard enough. You have to make changes keeping in mind the limitations of the human mind and behavior if you want to create a viable real-world solution.