Even taking many of this quote's assumptions for granted, I'd question whether it's always a bad thing to be weak. Some weaknesses can be strategic - for example, building failure modes into your designs allows them to fail gracefully rather than causing a catastrophe. In this case, I think that being offended by certain words can sometimes have utility because that offense can be used productively in a few different ways.

1. Offense can motivate people to try harder in their struggles against injustice.

2. Offense can be useful for persuading other people of a viewpoint.

3. Offense can cause people to act in ways that are costly but deter others from doing certain things.

The reason I make this point is because I feel that when Stanhope uses the word "weak" what he really means is "coming from a worldview I dislike". I'd be highly surprised if Stanhope was unoffendable himself, if he didn't care about other people's words or thoughts at all. Indeed, in this quote he actually seems to be offended that other people get offended, in a lovely display of hypocrisy.