Bhagavad Gita, Chapter 3, Verse 26

One should not unsettle the mind of the ignorant who are attached to action; rather, the wise, acting steadily themselves, should engage others in all their work.

Talking someone out of the only motivation they currently have, without giving them something real to replace it, just leaves them stuck.

Pulling the rug out from under someone's reason to work, before they're ready for a deeper one, doesn't elevate them, it just confuses them. Better to keep working with real integrity and let that example do the teaching instead.