BS. Between about 75-95% of the greenhouse effect on Earth is due to water vapor and clouds. And water vapor is almost entirely of natural origin, something like 99.99% of it.
No argument with that. The question is whether CO2 warms (yes), increasing it warms more (yes, but only logarithmically) and whether the extra CO2 in the atmosphere is manmade (yes). Manmade water vapor is negligible and water vapor is regulated by weather so under solar and ocean cycle control, not controlled by CO2 or CO2 warming.