As indicated at the download page and in SourceForge.net download page, the portable version is available here (285 MB).
As you finally figured out, nothing is hidden and there's also no "tyrannical freeware shenanigans", because nothing is deleted in your back (your SH3D files as well as the imported 3D models / textures). Whatever you design with Sweet Home 3D, your SH3D files are the files which count the most for me, and I'm sad each time I can't repair a damaged file.