I am not saying you sell it all. Maybe make some profits out of it so that you can be ready to buy back if the price turns south.
Just leave some to avoid a larger regret. It wont hurt that bad if a sudden increase also happens.
You're absolutely right, but it doesn't always work out well. I'm sure that people have done so already well below the current levels, but have been disappointed because the price went up way higher.
I think the main point is for people to educate themselves on how a market works on a more technical level. Selling, even when it is to secure profits, isn't always the best options and might result in more harm than good.
It sucks having sold at $6000 thinking to have done a great job, to not long after that see how the price keeps pumping further. This is a hodl market until we're seeing clear signs of a bearish reversal.
I would like to add that people also have to make up their minds about what they want to be in this market, a day trader or an investor. they can not be both at the same time and make moves that belongs to either category any time they want.
if they are traders then selling like this to secure profit is always a good idea but a trader has to always be super active going in an out many times. sitting around and hoping is not good for them.
if they are investors then taking profit out after a small rise is silly, they should not be active in the market at all. instead they should only buy the dips and accumulate that way and wait for long term results. which usually means cashing out profit inside bubbles (such as $20k)