Anyone can release the source code of any application, for that it's not necessary to claim for movements or accompany a logo or a name. That's rather common in academic endeavors, or for those whom like to establish collaboration environments. There are other possible reasons because open source increases the possibility of creating better applications and learn more when someone warns about a mistake or adds ideas. It's also expected to see who tries to swank about coding skills or in other interrelated field. How it be, to create a necessity works as a claiming mechanism for companies in the task of increasing sales. If there's no other option, if the user wants a specific application, and the price is high the only legal solution is to buy the software or build it.
In fact that has some in relation with the idiosyncrasy of different people. Altruism versus greed was there for a long time; in the more primitive evolution states, the second was almost hegemonic. For instance an insect usually acts with greed for resources, it only thinks in itself. It's rare to see some primitive species sharing some resource with other because it escapes from their way of looking things.
Capitalism is not bad in a technical conceptualization, the principal problem appears with greed as some people encounter an excuse to solidify a biased distribution of resources (principally economical, and it touches numerous aspects) for creating the anomaly of differentiation between individuals that scientifically don't have practically dissimilarities.
If open source appears in a scene where multiple companies compete for creating better products at a low price of production, it statistically starts chances to appropriations and multiple uses of that source with the goal of earning revenue, maybe parasitizing the work of others. Although the word "parasitizing" is arguable since anyone that publicly exhibits the source should account with it, so it's perhaps better to say a form of symbiosis where one part could dislike —strangely both— the other.
The funny question is how these two realities would coexist without giving origin to large actions of that euphemistic symbiosis.