I think it's more about a fascination with a puzzle that is very difficult to solve. 200+ don't normally die at once without any explanation as to root cause.
It's not the number of people - modern aircraft are built to be extremely airworthy, and if a plane goes down, it means that many things at once went terribly wrong in a very unprobable sequence.
I don't know about you, but yes, I've read railway accident post-mortems before.
We have sort of a professional interest here. We may not all be airline avionics engineers... we may not be any of us airline avionics engineers... but the failure of complicated systems is certainly something we all have to deal with, hacker or startup founder, and learning about them is not time wasted.
If most of the train ends up either floating in the ocean or a couple miles under the surface, you would, at least, have a very interesting trainwreck.
