I actually really like being this early on the platform, last time that happened was Google+ and that went nowhere. But this time it feels like you can actually contribute to the platform. This can be done by posting interesting things, just chatting in the communities you like, and can even help with the development of Lemmy if you have the skills.
I hope this will be the first Open Source project that I can help, I always wanted to contribute to open source, but that never went further than publishing my own projects (that were way too specific to be useful to anyone else) under an open source licence.
The article makes some good points, cooperation can easily get greedy when their platform gets too large. It does feel like it tries to connect FOSS to privacy, though, and that's a bit more controversial, especially when it comes to the Fediverse. For a platform like Lemmy the most important thing is to share the post that you published, there is limited development time, security is hard, and when things go wrong it is hard to point at someone.
For example, sending private messages often leads to these private messages being readable by the admins of the instance. In the same way, instance admins can also see the email address that you provided. So we just have to trust the instance admin to be capable enough to protect our data and not leak it out on the internet.
Of course, these issues also exist in companies that want to push out new features to attract users instead of spending time to test if everything is secure. It simply is a difficult point for both FOSS and commercial software, and we need to hold both FOSS and commercial parties responsible for respecting our privacy. At least with FOSS, we can switch to a fork if a maintainer does not do their job well.