Interesting situation and probably relevant to many on HN, but at the same time it feels weird to be highlighting the "struggles" of people in this situation when so many others are going through such deeper hardship.
Well, "this" will stop one day. People who have a boatload of stocks and cash aren't the ones who are impacted the most. It's those who live paycheck to paycheck and have little to no savings. It's just a matter of liquidity. Yes, it does hurt to withdraw money during a crash but that's just a tiny sacrifice compared to people who cannot pay their rent because their employers (e.g. restaurants) have closed down.
If done right, this is planned for. Yes this year will suck but it’ll go back up and the so called “safe withdrawal rate” accounts for such dips. Besides it’s easier to pick up part time work for a year if you retired before 40 if you need to top up your income than if you retired at the prescribed 65+ years old and are too old to work anymore.
It's also a good learning experience. As you said, messing up your retirement at 40 isn't as bad as messing it up at 65.
I would hope anyone who "fires" would have some kind of plan for a recession. This won't be the last one.