Sorry, but I’d fundamentally disagree and say you could lay blame on “human error” for this one. Not as the root cause, anyway.
The operators did everything they should have to shut down the reactor. If anything, it was the flawed design of the reactor and the fact that they were never properly told about the minimum number of rods required to stay in the core.
From memory they needed to leave something like 20+ rods in the core at all times and shortly before the explosion they’d removed all but 8 or so (don’t quote me, but it was vastly below the recommended minimum)
I’ve been a safety manager of a Power Station and can tell you that those guys would have known those systems inside out, and they’d have followed the orders/arrogance of the lead engineer to the letter but human error was merely a contributory factor.
I also feel that those guys probably lived with the shame/blame of such a horrible accident being pinned on them, which doesn’t sit right with me.