My initial response to that response is it's too easy a simplification
I believe when done right that the simple life can be easier. Depending. The farm example is one that is far from simple or easy, and interestingly is the one that Thoreau used as an example of a life of quiet desperation. I have lived simple and easy times. Typically what one gives up rather than ease is confusion.
When you have little, there is little to do, and you are left with a lot of time on your hands that you can't afford to fill with entertainment and distractions.
You are left with a lot of thought, observation, and ultimately yourself, which might be the scariest of all.