You know what, I don't agree. The rule is actually simple; you buy Bitcoin and keep it safe. That's all there is to it. What's not easy with that?
The thing is that people are complicated. We want to trade. We want to analyze charts, develop patterns, make strategies on the best entry and exit points, and so on. We want to invest in altcoins for better opportunities. We get into ICOs, IDOs, DeFi, staking, and so forth. And we are emotional, too.
But what is there in the entire history of Bitcoin that says mere HODLing is not the best thing to do?
Analysing charts, developing patten & strategies and realizing the best entry and exit period when investing in crypto are all very important, you can always buy and hold coins but when you put all these into consideration it reduces the possibilities of your loss.
There is more to trading or investing in bitcoin than just buy and hold, it requires knowledge and understanding in order to be successful.