Let's take a longer term example. Let's say that someone came into bitcoin in 2014 and spent a couple of years accumulating bitcoin, so maybe he accumulated around 50 BTC at around $500 each. So his total investment is $25k. So when the BTC price shot up to $2,000, he could not resist, and he sold all of his BTC, and so he ended up selling them for $100k, and so he has around $75k in profits... that is pretty good, right? He is still not doing as good as the longer term investor who still has the 50 BTC, and maybe the longer term investor has more BTC and his average cost per BTC is more than $500 per BTC.. we can imagine a lot of scenarios, and bitcoin has tended to be a good investment to hold onto for the long term, even if you might get enough BTC and you might want to shave off some profits along the way, you can still consider your investment as something that you mostly hold onto rather than converting into dollars and then ending up with dollars or some other inferior investment or maybe consumption good that you would be better off to have more BTC at a later price, even if your cost per BTC might end up being much higher.
I have seen many people who earn bitcoins and manage all their life expenses with it. I agree with you that investment in Bitcoin needs to be long-term. Because it is not possible to extract full profit from Bitcoin if not in long term. According to me, some part can be spent for special needs and the rest is better to invest.
if you understood what he is trying to say rightly, you will know that although the emphasy has been more of making investment on a long term bases, short term investors also have profit in Thier investment, it's only that it is more profitable to invest in the long term with a greater amount of Bitcoin than investing a small amount and because people are talking about taking back Thier investment you join them in doing so without necessarily understanding that most of them might have been HODling for a longer period of time compared to you and that they might have reached thier investment goal which place them at a good position to selling at the moment.
Regardless of the reasons given to you on why long term investment is better than HODling for a short period of time, the decision to leave your investment for long is totally up to you to make and the truth is that as long as what you get at the point you decide to sell off your holding is bigger than what you've invested, you've gained your profit and if the amount you sold your holding meets your investment goal, then that's good enough.
Everyone has different Bitcoin accumulation trajectory and so you have to be focused enough not to allow someone that bought Bitcoin ten years ago when the price was small and that had been accumulating since then and wants to sell at this current bullish period to become the reason why you want to sell your two year holding that's not even up to 0.05
BTC.
Regardless of how you look at it, long term investment will always be more profitable than whatever short term investment.