I agree.
The only study I know of that has compared flushed to unflushed cannabis found no significant difference in the chemical makeup between them.
The harsh taste is due to chlorophyll, which can be removed by restricting nutrients early or curing.
EDIT :
And from your link
The levels of nutrients concentrated in plant tissue are up to 1,000 times more concentrated than those nutrients in the root zone. One-hundred ppm nitrogen solutions produce plants whose leaves can contain upwards of 10,000 ppm of nitrogen. Since we have established that none of those 10,000 ppm are going anywhere but within the plant, we are looking for explanation of how that concentration is being reduced by a flush to the extent it can affect flavor. We haven’t found it yet.
But that is all I will say on flushing here, as it is not my thread. This would be a better place to have that discussion.