Looks like it's scrolling in general, not just trackpad. It appears to limit the maximum scroll speed when I'm using a mouse. I take it this is because the app is programmed using some kind of non-native controls?
I noticed on Windows that if I have the window in focus and scroll, each notch of my scroll wheel scrolls 4 rows. However, if I have another window in focus and hover over the Modern CSV window and scroll it will scroll ~90 rows (not always the same for some reason). The max scroll speed is the same in both scenarios, which I tested using a free-spinning scroll wheel. After some more testing it seems a lot of programs handling scrolling differently between these two scenarios, but it is much more obvious in Modern CSV because a single notch scrolling 90 lines is quite a lot.
I would like to be able to have some kind of scroll options available, choosing between smooth-scrolling or scroll by row/column would be great. Removing the scroll speed limit would be good too.