Everybody has different trackpad habits and they can be hard to put into words. For example, trackpads used to have buttons at the bottom, and you'd naturally use your fingers for pointing, and the thumb for clicking. Now the buttons are gone, and new users click with their index fingers, which can be tiring and inaccurate on some trackpads (especially older/cheaper mechanical ones).

Right-clicking also has a history. Because Mac trackpads only had one button (unlike PC touchpads), the way to right-click was to point with either your index or middle finger (high precision), then put down the other of these two fingers on the trackpad while doing the thumb-click. It will not move the cursor, so there is no loss of precision. At least that's what I did for a long time. (Although I don't lose precision if I hold down two fingers and press with one of them either.)

And it gets more confusing when Apple changes the defaults. They've flip-flopped between touch-to-click and press-to-click at least once. I'm not sure if using the bottom right corner was ever the default for right-clicks? And then they also removed the video clips that taught you some gestures in the system settings. And I think the whole "deep press" gesture is an anti-feature that only confuses people, the dictionary lookup used to be a three-finger tap and that was fine. But the Magic Trackpad 2 needed a headline feature, sigh.