Couple things.
1. the new port status monitor is actually a completely separate project from the old one (done in a different language and tool set) - so installing it wont replace the old version.
2. Tools put on there by the Unity install are done with a basic XCOPY approach - each tool is not installed with something like Install Shield separately so they wont show up in the add/remove program items (they get removed if you uninstall Unity of course).
3. The setups for each individual tool are smart enough to update themselves and their links in Tools Depot. In this case the new PSM is not a straight replacement for the old one - it wasn't decided to discontinue the old version (it will be in 8.0 I believe).
4. If you want to yank a tool from the Tools Depot (I assume this is what you mean, not Advanced Tools) - you can do it in the registry:
Go to HKLM\Software\Active Voice\ToolsDepot\Switch Integration Tools\
there you'll see folders for a few tools including the Port Status Monitor and presumably the Port Status Monitor new - you can delete the key(s) for the tools you don't want to see in the depot - when you start the depot next time they wont show up.