There are political, practical and aesthetic reasons to choose GNU/Linux as an operating system.

Political Reasons

The Linux kernel, various components from GNU, a large part of the software library etc. are released under Copyleft licenses such as the GNU Public License (GPL), which cannot be revoked. This prevents a lot of evil shit the corporate world likes to do with software. It also menas it can't be taken away; My license to copy, examine, modify and redistribute the Linux source code is irrevocable.

The kernel and much of what goes into a Linux OS these days are largely developed by larger corporations (Red Hat is now owned by IBM) but a lot of the app ecosystem is community driven. A lot of applications in the Linux ecosystem exist because someone wanted the tool to exist, not because someone begrudgingly accomplished something to increase shareholder value.

Practical Reasons

The vast majority of Linux distros are provided free of charge.

The majority of Linux distros are lighter on system resources than Windows; Windows' system requirements have forced a lot of perfectly functional hardware into retirement where they run just fine with Linux.

With a few notable exceptions the Linux ecosystem is free of the ads and spyware built into Windows these days.

Microsoft has a habit of rearranging their UI kind of for the hell of it, meaning constant retraining for users. In the Linux ecosystem, only Gnome is in the habit of making drastic unasked for design changes, and it's very much not a user's only choice.

Microsoft has a lot of monetary incentives to be user hostile. Not a lot of people use the Microsoft Store to search for software because much of the software the userbase wants competes with a Microsoft product, so they aren't found in the store. For example, Edge is the only web browser found in the Microsoft Store. Microsoft will not distribute a product that competes with one of their own. A typical package manager on Linux is full of actual useful software and is the preferred way of managing software on Linux. In fact, Windows is basically the only platform that hasn't managed to make a package manager or app store the default way of handling software.

Microsoft has been eroding the end user's ability to control or even own their devices. Linux does not become unusable for several minutes due to updates the way Windows does. Linux doesn't routinely take away features the way Windows has been doing lately.

Aesthetic Reasons

Windows is becoming less customizable as time goes on. Linux is only getting more impressive. It's not difficult to make the experience YOU want on Linux. Windows doesn't let you put the Taskbar on the side of the screen anymore. Get a load of this, I'm using Fedora KDE right now. By default there's a thing that works very much like the Start button on Windows; icon in the lower-left corner that pops up a menu from which to launch applications. I can right click that, click "Show Alternatives" and I can have a full screen thing similar to the MacOS launcher, a smaller cascading menu type thing that works like the Windows 85 Start menu, or by default a two-pane thing that's more typical of Linux systems. It's just so much more flexible.