It was just silly, that's the point. He is so into trying to get his bike back that he is showing all his friends the evidence, most of which is irrelevant, like the pen he bought one hour before his bike was stolen.

I think there are scenes that are designed to show how ridiculous the movie is, including this scene. Another one that comes to mind is the lady in the magic shop - watching the movie now, she seems to be how people would react to Pee-Wee in the real world.
For the record, I think this movie is ridiculous in a great way!

My guess is because Pee-wee was still going through withdrawls because of his missing bike, and needed a lot of company. But I think the real reason he gathered everybody in town that he knew was so he could illustrate for them what happened in every single, MINUTE detail that his bike was stolen, when it was stolen, and the vicinity in which it was stolen. Basically asking them if they could help him find it or if they saw anything. Because at this point Pee-wee had eliminated Francis as a suspect after the confrontation at his house, so now it could've been ANYBODY. In a nutshell, he was saying, "my bike was stolen. Did you guys see anything? Can you help me?"

Suppose to mean?? SUPPOSE TO MEAN?????? !

That was one of the funniest parts in the movie.

The point of the meeting was to help him find his bike.