

In a way it can be seen as a “bot” since how it works is like what feed bots are doing.
Regardless, groups are by nature “boosters” even in silo SNS. Example, FB groups pushes group content to people’s personal timeline/feed.
It’s similar to how mailinglists work. You send an email to the group’s mailinglist address and then it gets boosted/sent to everyone subscribed to that mailinglist group/address.
So, yeah, technically “bots” since its automated forwarding.
Hashtags is like search without the noise. (Unless of course someone is abusing it.)
Groups are similar to hashtags but without the restriction on what content is allowed as long as it is within the agreed scope. Groups usually have moderation features as well. And it can also be set to private (if supported).
Even if a group is public, if the feature was well-made, replies to a post posted in a group are usually seen by griup members only. Or, if the thread itself is opened.
Compare that to hashtags, replies will always appear for everyone.