Browse host is a topic that some people agree with & others don't. To see this point have a look at this thread: BROWSE HOST (Should it be Optional?)
Personally I feel like you do!

AFAIK Searches such as a browse search are charged with a certain amount of energy. If that search is exhausted before all the information is complete then it times out. I've browsed people I was downlding from but the file I was downlding was not listed in the their files listed after a browse. lol So obviously not all of their files were able to be identified before the browse search timed out.

It is much easier to browse someone if they have chat enabled. But even if they do or don't doesn't necessarily mean you can or can't browse them. I've browsed people who don't have chat enabled. But it definitely makes it easier if it is enabled. On the main interface, it's a little easier to browse someone from the downld window than selecting them from the search results even if you are downlding from them. Which is a little odd. As far as people uplding, yes it seems mostly only those with chat enabled can be browsed.

Oh keep in mind that when you browse someone, it includes that person's files but will also add to the total some other people who have the identical file. So if you have a look under the # column you may see multiple sources for that file. Browsing is not always reliable. Hope that's of some help.