People who write and speak wordily may do so out of habit. Habit, though human, means behaving automatically, without question or deliberation. We neither read what we write nor listen to what we say. Often people are wordy because they know no better. The clich is king.
Nothing is so reviled as individuality.
We imitate one another lest we be left alone. We want to fit in, to be part of the crowd. We want groups to engulf us and institutions to direct us. Habits must be broken, ignorance overcome, and imitation resisted. But even if we do achieve all this, there are other possible reasons for our wordiness, less understandable and forgivable, perhaps, but human all the same.