Yes, it might sound worrisome, but I dont think you are pushing authoritarian ideology by using Lemmy. The code itself is fine. The code is not authoritarian. The server which hosts your account is also not authoritarian.

Lemmy is, right now, the best alternative for a reddit-like platform. It is something created for the users, by the users. By using lemmy, you are not enriching the wallets of the shareholders. By using something like reddit, you provide content and a select few get to buy a new yacht.

Also, plenty of people are contributing code to lemmy. It is no longer just these 2. The code is also Open-Source. Anyone can fork it and create a new version of lemmy, with compatibility with the current version of lemmy. By using lemmy, you are allowing the possibility that, at any time in the future, someone else comes and says “I have some ideas to improve lemmy, let’s do this on my own terms”, forks it and continues the work without massively spliting the community.