You don't understand Bitcoin traders: They have a binary view of investing in which you are a bull all in 100% of your net worth in Bitcoin, possibly with leverage, or you are a bear with 100% fiat and possibly short position.
I think that you are correct that there is a lot of that going on in the bitcoin space.. and really, there is a bit of human nature in the practice of investing heavily (and maybe even tending to want to invest too much) into something in which you are very bullish about its future performance..
Sure, inadequate protecting of oneself and one's investment pertaining to possible downsides seems to be common in all areas, and accordingly it is unfair to characterize all bitcoiners to be like that... because there is probably a pretty decent percentage of bitcoiners (possibly 25% or more) who are fairly moderate in their approach and attempt to take adequate and meaningful measures to protect themselves regarding both the upside and downside.