Sure, all of which are problems which we've since fixed. But the core point is that there wasn't a major release of radiation like Chernobyl, and the reason why is because there were a regulator-imposed safeguard in place: the containment building.
There were a lot of things that went wrong in 3MI. Many of the lessons learned from that were incorporated into future designs. But one thing that went very right was that there was defense in depth, so that a N different things would have to go wrong to create a nuclear disaster. And in this case the number of failures was less than N. That's an engineering and regulatory success story.
A large amount of radioactive krypton gas was "vented", meaning it was released to spill down to the river and gas anyone who lived nearby. There was no tracking, so we don't know who or how many were exposed, or how much.
We can certainly ballpark estimate how much gas was vented--we knew the pressures and duration of the vent.
But this is a night-and-day comparison with, say, Chernobyl where the core was exposed and burning unmitigated for nine days. Many more orders of magnitude more release of radiation.
Everybody agrees Chernobyl was the worst. But that doesn't mean the others were picnics. A common thread is systematically discounting harm to people exposed. With such pervasive dishonesty throughout the industry, rigorous oversight has proved impossible, in practice.
The nuke navy is always cited as having no incidents, but that doesn't pass the smell test. Military failures are easily classified and buried.
There were a lot of things that went wrong in 3MI. Many of the lessons learned from that were incorporated into future designs. But one thing that went very right was that there was defense in depth, so that a N different things would have to go wrong to create a nuclear disaster. And in this case the number of failures was less than N. That's an engineering and regulatory success story.