Hi .. Your annoyance is understandable, but you should realize that not all the hosts you cannot browse are trying to stop you browsing. I use Phex and Limewire. Recently a friend tried to browse my shares and they could browse the phex ,... but not the Limewire. I could browse them no problem. Next time we try, I expect something different will happen. I don't know why this was. At other times people will download on one machine and uploaod on another, firewalls and machines running on networks can cause problems, and other factors such as whether a host has chat enabled can make a difference.
If you search the forums. (Search button .. above right) for Freeloader or Browse for instance you will find the subject has been covered many times.
There are freeloaders and leeches out there, but it is almost impossible to tell who they are. I once was about to ban a host uploading a lot of stuff of me, but I searched for the files and found them being shared from a totally different ip number, along with thousands of other files, and this was in fact one of my best download sources at the time.
So don't jump to conclusions too quickly