Lemmy is an infinite feed of empty bitesized content. It may not have a purpose in feeding you, but it does all the same. Or what do you mean by "feeding"? I interpret that as presenting you with the mental equivalent of empty calories. It's not motivated by ad money to do so, but that doesn't mean it's not motivated, or that it even needs motivation to do so. In fact, Lemmy is largely just a reddit clone, so simply by copying reddit it inherited many of the UX design choices.
All social networks, including federated platforms, use "algorithms" to surface content. The algorithm that Lemmy uses is very simple, but using a more complex algorithm is not inherently bad. People use "algorithm" as some kind of boogyman word without understanding it or considering what it means.

To not be a hypocrite you should treat all social networks with a similar critical eye. I'm not gonna say that they're all equally evil, but when you criticize something that other people like, then you should be willing and even eager to turn that same eye on the things you like.
I am concerned about those things. I do very little about it. It's a cost I just have to be aware of when I use these services. Specifically wrt social networks I stopped using the ones that don't bring me enjoyment.

Wrt Tiktok specifically, I find it less predatory than the other for profit platforms, but I don't blame people for not using it if they don't like it. I just check myself before I say anything elitist about social networks preferences