Seth was no stranger to the presence of hundreds or even thousands of different sensory inputs being crammed into his head. However usually he kept most of them blocked out, turned down to the point that he didn't actively look at them and only paid attention when something, such as a [Spirit Animal] alerted him of something that needed said attention.
Even with his evolved brain, keeping track of so many different view points would be nearly impossible.
He had also gained that many puppets gradually over the last few months. So there was a difference between adding one pebble to the pile, and having the entire truckload dumped on top of your head all at once. Thus, resulting in the skull splitting migraine he was currently experiencing, and which was causing him to writhe in pain at the moment.
