The way I understand the ActivityPyb protocol, it is Publisher/Subscriber paradigm. That means when you federate with another instance, you receive (Subscribe to) the things they Publish, and they subscribe to the things Hexbear publishes. So they don't "reblog" Hexbear just because they receive Hexbear content. Their users would have to deliberately reshare the content in some way (on Kbin/Mbin, this is done by Boosting, on Mastodon it's Resharing, etc etc).