Not really. I mean that “because…” part.

Leftism is inherenty tied to technology, especially new. It’s part of its lifestyle. EVERY new, massive social “site” (or online service) is expected to be left-leaning by default. It may later change its political viewpoint, but in its relative infancy it’s left.

Rightism is more about actions taking place in real-world. As such, the technology isn’t perceived as more than a tool, used for specific purpose only, rather than part of, or the foundation of a lifestyle.

…and of course there’s a plethora of alternative political views, options and convictions that are a mix of either extremes of the spectrum - if you meet a person online, it shouldn’t be surprisied to learn about “pro-life”, but also “anti-Trump” and similarly puzzling approaches to various aspects of life.

tl;dr: it’s not about bots. It’s because Lemmy/Mastodon isn’t popular enough to serve as a tool for right-wing politics.