DCA method is an investment method through which you can buy Bitcoin at any time at any price. DCA method never helps you to hold your holdings long-term. Holding it long-term depends entirely on you.
Yes long term holding requires long term planning. There are many people who bought bitcoins using DCA method but could not hold them for a long time, it is seen that many panic and sell them. DCA strategy is the way to slowly accumulate bitcoins and DCA strategy is the way to buy bitcoins at an average price. So long term planning is required to hold long term investment, no one can succeed without planning. Before doing any work we need to plan, if you can't hold long term then investing in Bitcoin is not for you, because short term investment can lead to loss instead of profit.
Maybe they get panic its because they still don't understand on what they are doing.
Long term holding is serious commitment that's why people need to understand the risk first on what they are doing and then prepare to have good cash flow to spend since this is important if they want to engage with Bitcoin since if they have sustainable income and could have lots of discretionary income to spend then provably that their chance to succeed is high and they can ignore those any potential threats that will just disturb them.
They are just one step to get broke if they engage on short term investment and there's good chance that they lose their money on recent massive liquidation happened recently read this one
https://cryptonews.com/news/over-1b-liquidated-in-24-hours-as-bitcoin-crashes-3-percent-worst-day-june-whats-happening/ That's why its better to be a holder rather than joining those people got panic and liquidated by sudden market shift.