You're telling people that they "need" to change their subjective appreciation of what constitutes beauty and aesthetic pleasure? I mean this as sincere constructive criticism, you will not win support for sustainability with such a demand. People don't enjoy being told how they "need" to feel about something as personal as aesthetic experience.

Focus on how sustainability is good for people and how it will improve their lives. If they prefer orderly, manicured lawns, don't look down at them saying they need to change their aesthetics.