I think you misunderstood the request to "share" there. They're most likely talking about boosts, Mastodon's version of Twitter's retweets. Lemmy, I think, doesn't implement boosts. So it makes sense you would interpret it differently from the rest of the fediverse.
Basically, this isn't a call to repost. It's essentially just asking to upvote and boost and OP can then see from where those interactions came.
why should I not remove this from !fediverse?
It's on topic and your community has no rule against test/experimental posts.
Your community might want some additional rules if these kinds of posts are undesired. Like a low effort rule maybe. Or a rule against posts asking for upvotes and similar actions. A quick look at lemmy.world's site-wide rules didn't look like such a rule is there.
FoxFairline
m_f