I want to have granular control over where my files are stored. If I want them stored in the cloud, I want that to be a choice I consciously make, not something that's defaulted at the operating system level.

So the hatred isn't really directed at OneDrive, it's directed at the fact that the operating system is making decisions for me, and they don't line up with what I actually want my computer to do.

I haven't used Windows in a few years (and never used OneDrive), so pinch of salt time, but...

I don't like the idea of M$ having direct access to all of my files and personal data

That and, there have been mishaps with OD deleting files

Also, i personally don't like software automagic, especially when i don't understand what is going on under the hood

Is OD just a folder? Where are my documents actually stored? What happens if my internet goes out? How much do i trust M$ to not bungle something or sell or leak my files?

If it lost your files after constantly fighting you about where to save them, you would.

Plus the whole not asking to install, then begging for money to upgrade a service you never asked for. Until you finally have to waste hours learning how to completely disable it and get it off of every machine you own....

That breeds some resentment.

Speaking of OneDrive being a hunk-of-fuck