The comment in question said "The price of hens has just dropped by 50%!". That's a bad time to sell.
If you can predict "the price of hens is about to drop" more reliably than the market can, that would make you exceptionally rare. And if you don't already know and have evidence that you can make such predictions reliably, the safe bet is that you can't. Many people try, and fail, and end up buying high and selling low.
There are a plethora of investing choices, including not investing. Bitcoin, Gold, Bonds, etc. If someone is investing in HENS right now, it's not unreasonable to suggest they may want to change their strategy for the next couple of years.
Similarly, if someone is planning on planting SOY, I'd try to talk them out of it.
Would you seriously not try to talk someone out of planting soy?
If you can predict "the price of hens is about to drop" more reliably than the market can, that would make you exceptionally rare. And if you don't already know and have evidence that you can make such predictions reliably, the safe bet is that you can't. Many people try, and fail, and end up buying high and selling low.