First of all we need to be clear here.
Flushing can be helpful when correcting a salt build up, correcting overfeeding etc.
Pre-harvest flushing is a complete and utter myth with no evidence provided.
People claim it provides better taste (removes chem taste they say), bigger buds, better high etc.
What I have disproved is pre-harvest flushing.
I don't see a problem in flushing your crop if you have a problem with pH, nutrients etc.
But pre-harvest flushing based on the reasons I mentioned is ridiculous and not proven to be in any way factual.
If you search my nick on the forums you could find the information yourself.
We have already had a lengthy discussion on pre-harvest flushing.
I will provide you with the link this time:
https://www.rollitup.org/harvesting-curing/496111-i-dont-starve-my-plants-15.html
You should read the entire thread (there are many others who rationally argue against pre-harvest flushing) but you can also just read what I've written.
I'm one of the few who provided scientific evidence (research, and books written by educated scientists).
The discussion started earlier than page 15, but I'm providing you the link to what I've written and what I stand by.
In that thread I explain;
How and where nutrients are stored in the plant.
Why they are not stored in the calyx (bud).
Those are the two main points of the main discussion I had in that thread with Gastanker.
If you read the thread entirely you will see how I disprove his statements with scientific evidence and how in the end he simply stops posting because he has nothing left to say, he was proven wrong.
Finally, a lot of these people you speak of are authors and normal people.
They don't have scientific degrees. They don't know everything.
You should trust science over personal belief ANY day of the week.
Many of the most celebrated cannabis authors have been proven wrong many times.
People just take their word for it without any evidence, which is a huge mistake to make, you should question everything unless provided proof.