The summer flow'r is to the summer sweet,Though to itself it only live and die (9-10)
In these lines, we might be seeing the speaker's understanding of isolation shift somewhat. It's hard to get more isolated than that "flow'r" that lives and dies only "to itself." This sense of isolation could be underlined by the fact that Shakespeare has shifted from talking about the plural "They" to this singular flower. But doesn't he seem to be portraying this flower in a pretty positive light? At least, that's what calling it "to the summer sweet" sounds like to us.
But if that flow'r with base infection meet,The basest weed outbraves his dignity. (11-12)
Here, the speaker seems to go even further in saying that isolation might be good for the flower. If the flower is at risk of infection, isn't that a good reason for it stay secure and protected, far away from whatever might infect it, or what it might infect in turn? Could this be an argument for the powerful people to keep their true natures under wraps as well?