I keep hearing people say they go to the fests to see friends yet much of the initial complaining has been about more actors not attending.
Many fans, including myself, go to Fests primarily to see friends. But as evidenced by how the ballroom is filled, or at least nearly filled for every Fest activity, quite obviously that is not the case with the seeming majority who attend the Fests.
I can't get my head around people planning their vacations around the convention though. That totally eludes me unless the they simply don't have friends at home or elsewhere to visit. I guess let's say it's something I wouldn't do or think of doing. If a bunch of friends want to meet up in New York and spend a week exploring it that's something else altogether. And that can be done anytime and not necessarily around a festival.
That explanation is quite simple - as even you have since admitted. The Fests provide many with a convenient venue at which they can gather to see friends from around the country (or even the world), all at reduced room rates which allow those who would otherwise not be able to get together with those friends the affordability to do so. And they can do so around a common interest even if they don't all necessarily attend every planned Fest activity.
And even jokingly, having or not having friends at home or elsewhere to spend time with is completely beside the point.