Unfortunately, you need to use the FTP protocol to download this tool. Do you have a dedicated FTP client? If so, use that. I just verified, and I can access the customization wizard. There is however a problem with the URL you've posted: The directory path is case sensitive. Try this instead:
ftp://ftp.adobe.com/pub/adobe/acrobat/win/AcrobatDC/misc/CustWiz1502020039_en_US_DC.exe
(This is the full path, including the executable for the current version of the customization wizard as of 7/3/2017 - if you are trying to download this after right now, that path may no longer exist, and you would need to use this directory path to access the correct directory: ftp://ftp.adobe.com/pub/adobe/acrobat/win/AcrobatDC/misc/ )