Relationships matter. Titus, as a church leader, relates to certain people in certain ways and their relationships with one another need to be constructive, too.
The word for "teaching" that older women are to do for younger women is not the normal word for teaching, but derives from the word for "self-control." What older women are to help younger women with is largely willful.
These relationships inside the church must be squared away for the sake of those outside the church (Titus 2:5, 8, 10). Not only is it clearly stated those three times, as he writes about relationships he breaks into rejoicing at the glory of the gospel.