Open source projects are often developed by volunteers, and hosted by free services like github or bitbucket. I've actually never seen an an freedom respecting

Open source projects are often developed by volunteers, and hosted by free services like github or bitbucket. I've actually never seen an an freedom respecting project that included adware, and I can confidently say that the reason for that is that if a team were to do that, somebody would fork the repo and remove the offensive junk. As long as it gets caught, it's a self healing ecosystem. The same cannot be said for non-free software, as the pool of people who could find junk is so much smaller, but also because if junk were to be found by an employee, they'd have very little power to actually do anything about it. Open source is volunteers, and when its not, they run on donations. When the donations stop, they stop. Some have found clever ways to make money, such as pay4premium or pay4support, but I've never seen ad injectors. Those come from third party distributors who aren't affiliated with the projects and can be avoided.