Running into a burning building (which in this particular case is the man's own house) to save his step-son that he dearly loves "absolutely could" (your words) make the situation worse and that's justification for handcuffing and tasing the guy?
Afraid I'm with roguenuke on this one.
"Don't run into a burning building" is about as basic as it gets. I mean, really. That's 2nd grade.
With no training, no protective equipment, no partner and no backup, he was undoubtedly putting himself into harm's way and had little chance of success. If he got in the way of the firefighters inside the building, he was increasing the risks not just to himself, but to the firefighters as well. If another family member, neighbor or friend ran in after him -- and the cops just let it happen -- then there is no question that will make the situation worse.
The police and fire department have not just the legal authority, but the responsibility, the obligation, the duty to stop family members from causing themselves harm, or their own deaths, by running into a burning building. That's their job -- to protect the public, even if it means doing things that individuals don't want them to do.
I also find your declarations of "self sovereignty" to be wholly unpersuasive. In many circumstances, it is undoubtedly moral to save someone's life. It is
not moral when you have a low chance of success, and doing so puts yourself and others into mortal danger.
While I sympathize with the stepfather, the bottom line is he was hysterical, and had absolutely no idea what he was facing. He could not possibly make a rational decision about his odds of success, let alone survival.
Using a taser might not have been the optimal method, and perhaps police today do rely too heavily on tasers. That said, I doubt the alternatives would be any safer or more pleasant.
The reports show that the boy may have been saved.
Unless they don't.
Firefighters deemed the building too unsafe to enter at that moment. The stepfather, again, had no training, no protective equipment or partners; he could have easily been overcome with smoke or fatally burned long before he got to his stepson. Just by opening a door, he could have increased the size of the fire. At any moment, he could have been struck by a collapsing section of the house.
In addition, reports show the family did try to save the child before they left the house, and failed in their attempt ("the boy's mother and stepfather were able to exit the backdoor of the house after an unsuccessful attempt to get to the boy sleeping in another room"). I see little reason to believe that his attempt would have been more successful the second time.
If the FD isn't going to risk their life to save the boy, why shouldn't the man be able to?
If a trained firefighter with the appropriate protective equipment can't get into the house to save the child, then a hysterical stepfather in his pajamas is unquestionably less likely to succeed.
And since it's the job of the first responders to prevent people from dying, that pretty much means they have a moral (if not legal) obligation to prevent family members from dashing into the house.
That boy died and it's a tragedy. That man will now live the rest of his life knowing that the boy could have been saved had the PD not handcuffed and tased him....
No, he doesn't know it. He may believe it, he may suffer because of it, he may be traumatized by the night's events. That doesn't mean his belief is correct.
You call it an "emotional state", the rest of the world calls in unconditional love.
The man openly admitted he was (and I quote) hysterical. Nor is hysteria mutually exclusive with love; if anything, it was the latter (along with the failed first attempt, and of course the situation itself) that caused the former.
His motivations do not change the fact that he emotionally compromised, which led him to act rashly and irrationally. The police may not have done it the right way, but they did the right thing by preventing him from running back into the burning building.