@Stephanie1231 The hosts may have had a bad experience with partiers trashing their home. And it's like pulling teeth to get Airbnb to pay for damages, and partier types almost always deny that they caused the damage and refuse to pay. (Not assuming you fall into that category, just explaining why the hosts may have declined)
Did it mention that families are preferred in the listing description and info? If not, I can see where you'd feel a bit miffed and they really should state that in their ad if they don't want groups of unrelated people.