It sounds like you didn’t manage to actually install that copy of Inkscape on your computer. Or, if you did, it ended up somewhere besides where it was supposed to be.
That folder location is only present on recent versions of Inkscape, so that may also indicate that you don’t have things in the right places. All together, that sounds like you may have more than one copy of Inkscape on your computer.
When Inkscape is open, hold down its icon in the dock to show the contextual menu. Then, select from the Options submenu there, “Show in Finder” to reveal the location of that copy of Inkscape. I’d recommend that you move it to the trash.