If you can run the bot yourself, then it's an open source project. The companies founding these projects make them available to everyone in order to entice developers to contribute to their project instead of paying them. They hold their own data and leverage that to make their money.

So sure anyone can deploy their own, but not everyone has access to the same resources. It's not uncommon for multiple companies to collaborate and in order to do that while ensuring one company isn't at an advantage, they open source the project.

In turn, this then becomes available to anyone to contribute to and use. What's good for the goose is good for the gander. None of these guys want to shoot themselves in the foot, so keeping everything transparent also maintains a level of integrity.

Then the code is typically protected by some licensing so no one else can come along, copy everything, and wall themselves in for profit without contributing to the project.