The history is that Lemmy was originally created as an independent forum for communists. Later, the devs experimented with ActivityPub federation and created the first federated Reddit alternative. The software itself is neutral and can be used by anyone, but the original communist users of Lemmy before federation was implemented are still around. The politics of Lemmy's original community scared off a lot of potential users from exploring federated Reddit, but bringing more users and awareness to Lemmy will also attract politically neutral developers who can maintain a good alternative.
An alternative is not even necessary if the devs are able to leave their ideologies out of the software's design, which I believe they are doing well.
Smiley