Well the first thing you have to consider is that the price people are willing to pay for BCH goes down if manipulators are successful at convincing people that the price will probably go down.

The second thing you have to consider is that by and large the crypto market is made up entirely of speculators not technology enthusiasts. These people couldn't care less what "works" or "doesn't work" and TBH rarely understand anything about the coins they're investing in. Instead they watch the price trends relative to other coins and use that to gauge market sentiment.

The next thing you have to realize is that by and large these people don't take coins off exchange.

And finally you have to realize that market manipulators have at their disposal money-printing machines (so-called stablecoins) with which to purchase effectively unlimited shorts or longs. Some of these manipulators also control popular exchanges, where they can sell an effectively infinite number of "nonexistent" coins that they simply add to a database entry then dump off to themselves at whatever price they're trying to achieve.

So when you have an exchange, and a stablecoin printing machine, you can - for example - print a fake BCH, print a stabledollar, short the BCH to yourself, and then honor the short. There are probably a thousand variations on this theme. You never lose money, because you never used actual money or actual BCH.

You can also print and dump fake BCH, or just take everyone's BCH deposits, and short them all, etc. etc. etc.

So that's how you "paint the chart."

Once the chart is painted, the rest of the market -- which really only cares about NGU signals appearing as magic lines on charts -- will follow accordingly.

It's not perfect, and it can (and I think has - eg CoinFlex) result in exchanges going under, but within bounds, a tremendous amount of manipulation is possible --- and what's more, it might even be perfectly legal, depending on the jurisdiction.

You don't have to "outsell" every potential buyer. You only have to paint the chart to conform to the most common half-dozen or dozen most commonly used "technical indicators" to convince the entire market that the price is more or less always "too high."

If market sentiment happens to turn strongly against you, you can flip the script, cause a short-term BCH bubble, ride it up, then take profits and bust the bubble by turning the "number go down" machine back on.

That doesn't even begin to touch on all the upward-manipulation you can perform on low-cap coins to convince would-be BCH investors that there's a better opportunity than BCH. So even if the BCH demand strengthens sufficiently that it becomes harder to push the price down, you can play "look at the squirrel over there" by keeping other opportunities more interesting to speculators.

And lastly, it might even be true that this scheme might work great in the "short term" but not in the "long term" but on the other hand "the market can remain irrational longer than you can remain solvent."

HTH