Most likely to save license fees, and the amount of the average audience who have a clue about open source file systems will be minimal.
The reason MS probably limited FAT32 to 32GB or under is to stop people who don't know any better formatting things like external HDDs to FAT32 for Windows use, when for most purposes NTFS will be the better option.
I can understand FAT on a portable USB stick to minimise write, or for certain specific uses/cross-OS compatibility/non-Windows boot drive, but for a normal HDD on a modern windows OS, internal or external, I'd go for NTFS over FAT32 these days any time. 4GB file limit just being one reason.
***
In regards to the OP question, Minitool Partition Wizard can also do this I believe.