its not a good investment strategy to simply hold.
It really depends on what you're holding. Many of the most successful investors have primarily got to where they are by investing in low-risk, low-reward investments and just holding them for many years (like Warren Buffet for example).
In Bitcoin's case, it's an even better choice to just hold if you're not much of a trader, because it's extremely difficult to predict the future prices when the primary basis for recent price has been speculation rather than usage.
why didn't I hodl my bitcoins?
You need to be questioning why you bought back in as much as why you sold. Both were equally emotionally charged decisions.
Holding is not a good strategy in general. Holding something for the sake of holding is not a good strategy and that is not debatable. Warren buffet has nothing to do with what I was saying, he "holds" but only because he is constantly re-evaluating the market and validating his risk management. He doesnt say "generally holding is better" because generally 99% of coins will fail, so then in that instant holding would not be good generally.
Its a nice meme, but some people think it is actually solid advice.