Can we get an answer to what this means? I was also surprised when I saw it.

In the first sentence, why is the disease free link connection with the large nursery a most statement and not an always statement. It says they ONLY sell plants that are disease-free does that not mean it should just be an arrow relationship rather than a most?

The initial statement is claiming that if you don't do both then it is not a morally good action therefore, the contrapositive states that if one of these requirements isn't fulfilled then it is not a morally good action. Basically, you have to satisfy both in order for it to be a morally good action, so if u don't do one or the other then it is not morally good. Hope this helped!