In general, I agree, but I think it depends on the context of the yard work. If you live in a rural area, cosmetic upkeep is optional, and you can work on things at your own pace. If you live in a "standard" exurban neighborhood, constant upkeep can be a chore, especially if you want to use your limited daylight hours after work to do anything else.

In other words, if you have control over aspects of the work, it's more likely to make you happy. This seems to be consistent with the findings in the article.