Er... the secure results are designed solely to help you. There's some features that LimeWire exposes that are kind of dangerous, such embedding a URL in a search result and sending the user to that URL when they click on it. That feature's very useful for sending old versions to an upgrade page when all other upgrade notifications aren't working, so we didn't want to remove it, but we wanted to make it hard-to-impossible for spammers/scammers to take advantage of people by sending them to sites that could compromise their computer. So LimeWire doesn't show results that have that embedded URL unless it's "secure".

As for the filtering, 4.11 has options for it.