I saw a comment somewhere saying the title and had links but I lost the comment now. One of the links was going to raddle.me which is a Reddit like site
The political views of the main devs are controversial but it doesn’t really matter since Lemmy is free and open source. No one owns or runs it. Only lemmy.ml specifically is run by the devs.
Spez, reddit's ceo, used to mod r/jailbait. Did it matter to the users? It didn't. Why should this be any different?
Also, this is a public platform as much as reddit is. Reddit's TOS is horrible and yet people stayed. Lemmy is not worse than reddit in terms of privacy. I had to use a script/program before deleting my reddit accounts because reddit won't delete what's in there.
According to the current readme: https://github.com/LemmyNet/lemmy#features you will be able to delete all your post with account deletion. This also align with the warning text before deleting your account.
Also most instance are hosted by community members, and are community funded. I think most instance don't have the interest, or even the means to sell your data.
However, by the nature of OSS, everyone can modify the code when they start a instance (however, as per AGPL, they need to release the source code of modification, but I am sure there are people out there sneaky enough that can modify the code without other noticing). So theoretically, the admins can track you. Also by nature of the federation, your data will also be present on other instances that is federated with yours, but what they got should mostly be public informations (namely information of your post). And they don't necessarily need to delete that info after you deleted your account.
That being said, the privacy aspect of these small community-funded federated service should be order of magnitude better than most other social media site, where their entire business model is to spy on you and sell your data.
Another conservation I had recently said that lemmygrad is apparently run by communists and harbors tankies. If I had to venture a guess, whoever wrote what you saw doesn't understand the difference between nazis and communists, and that's where it's coming from. Or maybe there's also a nazi instance here somewhere, but as long as you're not part of their instance or an instance that federated with them, you won't see any of that shit
Having said that, you're free to join a different instance (like the one I'm commenting from), if you have issues with that. I haven't personally noticed anything actually problematic though.
Edit: quick answer -> definitely not neo-nazis, and probably not relevant either
As others have said, so what? It's decentralized platform. If you don't want to interact with them, then don't. Nobody runs lemmy. It's a collection of instances communicating with each other. That is the beauty of it.
The only data you give them is stuff you post on there. If it's sensitive information, don't post! I mean, obviously your stuff is going to get stored in the instance you post on. If you don't think whoever running the instance should have that info, don't give it to them!