Two seconds is kinda close, no?
The first time I went on a group ride (and it was the group training ride) it did seem a little close but once we were riding for 10-15 minutes, it felt comfortable. It's assumed that you "... have control of your motorcycle ..." and there are several "leads" on each group ride: ride captain (leads the group), sweep (controls the rear) and likely at least one more ride lead in the group. The leads are connected with CB radio. The initial group training ride pauses at least once, and leads provide feedback. If someone needs more time to master their bike and riding conditions, a lead will speak with them privately.
Another benefit of the group: experienced riders take newbies out solo or two at a time for rides to work on basics (hill stops/starts, turns, panic stops, etc.) to ensure everyone is at least at or beyond a basic level of motorcycle control. All this "lead" time is voluntary, and we pay $5 towards Meetup expenses a year. These rides take place around Boston (where we're based) so the new rider doesn't have to travel far to get to it.
I just participated in a large group ride, Nelson's Ride
, with several hundred motorcycles in a group. Everyone followed these guidelines (MSF), and intersections were blocked by police and volunteers. We rode about 50 miles without stopping and with no accidents. (The only issue for me was jaw soreness from checking out the bikes when parked before and after the ride: some amazing custom bikes.)
It does take some getting used to, and I go on a group ride whenever possible to maintain that level of focus and comfort. I practice that, too, in traffic when I am out solo: 2-seconds spacing to the car in front of me. More at night and in the rain. The group moves quickly and avoids issues with 4+ wheel vehicles this way. It seems a huge advantage when riding in a group on the road, but to each their own, too.