I put in bold the part specific to your install issue
Nothing wrong with the OS, it's the methods you are using. Basically you are using the wrong tool, and then being taking your frustration out on the OS. For many reasons the web browser was not designed to install applications onto the device directly, please read below.
You have two options, neither require a computer or internalz or a patch.
If the link is to an .ipk you can throw the URL straight into preware using Install Package. (I used this method last week to load keyboard patches that were hosted on a file server that would not let me download the ipk properly, copy ipk link from file server and let preware do its thing.)
Since this doesn't link straight to the ipk, once you have used the browser to download, you will still open preware and go to Install Package, but instead of pasting a URL, you will tap browse. Then browse to the downloads directory, tap the file (will be ca.canuckcoding.************.ipk) click okay at the bottom. You will now see the file path in Preware, you can the tap install.
Easy peasy as they say. OS working as it should, no OS is as open to hacking as webOS (other than linux, but that doesn't count in this conversation), you just have know how to use the tools provided by the awesome homebrew communities. OS's, especially in the mobile platform are built with certain security to ensure the end user is safe and some times so the end user cannot modify the source os (iOS and certain android boot loaders are good examples of this).
To add, even with open source, I don't see the web browser being aloud to directly load ipk's being added by HP. The only thing that may happen, is the homebrew community will have the source code and be able to build a "plugin" of sorts that would redirect an ipk file to be opened in PreWare. Even then I don't see this as being a priority at this point for all those working on Open Source, everyone involved, HP and homebrew alike has more than enough work to do.