Because for the previous 15ish years before Musky got a hold of it it was actually decently regarded. Many people turned to it for up to date news and trusted it. It was a place where brands could interact with customers, celebrities with fans, etc. It had built up trust. People are having a hard time letting that go.
Maybe you feel smart for dropping the name, but in reality those two have about zero things in common other than they both have some connection to space. Not personality, not their views, not their background have anything similar.
Even today there are top posts on Lemmy that are screen caps of Twitter. Not even Lemmy users can stop reading Twitter and upvoting. I down vote them on principle but it's 100 to 1.
Reddit and by extension Lemmy were designed to enable content aggregation. I dislike people having so few principles in general but the system is working as intended by users posting things they find interesting happening elsewhere.