it's clear, but missing the point. When you fill the car with gas, you do so with the car OFF, and a whole host of safety systems in the car, pump etc to avoid spilling and/or igniting the gas. The gasoline is essentially inert and stable during this process, and the safety systems are mostly mechanical (seals) and in the pumps (vapor detection).
This is totally different from transmitting vast amounts of electrical energy at high speed into a battery, which is an active, exothermic, chemical reaction. And that process must be actively monitored and controlled by the car using a whole host of sensors and software, in addition to various high-voltage circuits that connect more or less directly to the SC connector. This is complex, unfamiliar to most mechanics, and dangerous if it goes wrong or is not properly maintained/repaired/tested. So yes, I do get why Tesla did what they did (but read more below).
As for the lit sparkler, that's hardly the correct analogy, since we are talking about the safety of the car, not the recklessness of the owner. Let's say you bought a rebuilt Tesla, and when supercharging it, the car caught fire and also gave you a severe electric shock when you went to try to deal with it. Would you say "oh well, that was my fault" or would you find a lawyer to sue the pants off Tesla for not making the car safer? If you stick a sparkler in your filler pipe, no-one is going to find the manufacturer liable, but things are far more murky when we are dealing with a rebuilt car of unknown quality. And like it or not, in the litigious US, manufacturers take steps to avoiding exposure to that kind of liability.
Now, having said that, I think what Tesla should do is contact you, explain that for safety reasons they have disabled supercharging on your car, and that they need to inspect the car to ensure it is safe for supercharging (possibly for a nominal fee) before they can re-enable supercharging again. While I sympathize with Tesla motives, they (not for the first time) handled things very badly (I suspect we are looking at Elon's stamp of personality on the company here).