Natural scrolling (Mac) vs Reverse scrolling (Windows)
I recently had to work on a windows laptop, and was frustrated with the scrolling. I faced the same issue when I switched from windows to Mac few years ago. It got me thinking why there are two opposite standards.
Assume that this article is a long physical page, and the user is only seeing a part of this page.

Natural Scrolling (Mac)
Natural Scrolling assumes that users are scrolling the page itself, where as the screen is static.

When a user touches a touch screen, the scrolling behavior is intuitive. The touchpad of a mac acts as a touch screen device.
Mac autohides the scrollbar and it is only visible during the scrolling to give the user an idea about the length of the page. Though it brings with it, its own set of new problems. Scrollbar is an excellent signifier to show the affordance of scrollability in a page. Sometimes the landing screen seems like a complete page, and user doesn’t scroll to check if there is any more content below.
Reverse Scrolling (Windows)
Windows assumes that the page is static and user needs to scroll the viewport(display), on the portion of page, user wants to see. If user wants to see lower part of the page, scroll down and vice-versa.

Another way to look at reverse scrolling is that the user is interacting with the scrollbar, rather than the page.
A Little History
Before the addition of scrolling wheels to the mouse, page could be scrolled through keyboard buttons-cursor arrow keys or mouse interacting with the scroll bar. For arrow keys, metaphor used was to scroll the viewport which seems more natural (By pressing down, users can view the content below and vice-versa). So the same metaphor was adopted for scrolling wheels to keep consistency.
The first trackpad scrolling mimicked how mouse scrolling worked. And the first scrolling mouse had physical wheels (many still do). If you imagine the scroll wheel sitting on a paper you were reading, the reverse scrolling direction is intuitive — the content moves in the direction the wheel would push it.
With the advent of touch screen, the natural scrolling seems more intuitive as the user is directly interacting with the page. If the user swipes up, the page moves up (mental model-it moves due to friction from the hands of the user like a real paper). A few years ago, Apple switched their scrolling direction to follow this analogy as the touch screen is growing in popularity and to support a uniform standard across its all devices. The touchpad of a mac acts as a touch screen device.
Windows haven’t switched to natural scrolling to support its legacy customers. Though it follows natural scrolling in its touch devices.