I see some echo commands in the batch file which never appeared when I ran it so looks like it didn't run properly?
It also looks to me like the bat file maybe assumes install on C:, which for me is a paltry 500GB boot drive, so I install all Steam apps on a 1TB SATA SSD and the Start10 folder is still there e.g.
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\TaskbarTextures"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\Uninstall"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\DeElevate.exe"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\DeElevate64.exe"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\DeElevator.dll"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\DeElevator64.dll"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\Default.spak"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\GroupPolicy"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\lang"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\Links"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\MenuTextures"
"E:\QVO ROOT\Temp Installs\steamapps\common\Start10\StartButtons"
Steam must know where the app was installed - it seems odd to me that the Steam uninstall missed this folder.
I'm guessing the pin to start10 option still appears in the right click menu because the registry commands in the bat file probably didn't execute either.
I'm thinking as a workaround I could reinstall on C: then uninstall again. If that cleans up the registry I can manually delete the folder on E: