You dont need to know the exact math formulas to the physics behind the inner workings of the internal combustion engine of a car to be a mechanic whos fixes those engines. You just have to know what tools are used on what parts, how to put it together and what the timings are on the gauges of the parts and tools.
The same principle applies to gardening, you don't need to know the exact DNA make up of a plant to grow and take care of the plant. You just need to know what type of soil, how much sun, how much water, how much fertalizer to use and how often to weed the plant.
That is why your state is BS.
Same prio
Sorry but that is a horribly simplistic example, would you be so confident if we made the illustration more representational? Say could you as a lay person repair a nuclear power-plant? which is getting close to the complexity of any given ecosystem on this planet.
"The same principle applies to gardening, you don't need to know the exact DNA make up of a plant to grow and take care of the plant"
Again if you want to grow more than just a single plant in other words maintain n ecosystem then understanding every process i not just vital is it a requirement for success. the largest biosphere experiment failed even with the top scientists from all 3 continents including the USA working on it.