Repeats by unknowns should not show up on your home timeline
When someone repeats a post. It typically pops up again on your home timeline as long as you follow the person who repeated it. That's fine, I think most people are happy with that behavior.
However, on Pleroma all repeat actions show up, even if you do not follow the person who repeated it. This is extremely annoying and unpractical. If a user's post gathers enough attention, they essentially end up drowning their timeline with their own post: Related post