this is a old argument, use search and find this over and over on this forum.
most L-users fear all and get a firewall, but never set it up right, so they are hiding and you don't get to connect.
as long as people can get something, they will mostly give back while online because it's not a big pain to share your folder.

so if you want to see more files, help teach more people how to set up a firewall or distribute a program that sets up popular firewall programs for them.