That’s not ignorance. There is no information in the post detailing what kind of study this was. It just says they all died. They could have died from anything for all I know from the headline. That is very misleading.
If the test subjects died from the vax and the vax was administered at the same dose/kg given to humans, that would be the way to phrase the information. If they gave a 100kg dose to a 1kg rat, I’d expect the rat to die.
Your rationalization is assumptive as well, and your example is not even possible. “100kg of something to a 1 kg rat.” This is how far you have to rationalize your defense.