I agree, but I'm not in the employer's shoes when they determine this, even after three days...
I suspect that this is a case of "you dodged a bullet" as much as anything else. Clearly, the employer has expectations that are unreasonable, at the very least, it's unreasonable to place those expectations on YOU. I'm guessing it's unreasonable for anyone, but some people are better at handling that particular type of abuse than others, and that's the people that the employer wants.
It's not a good thing that they have those expectations. It probably IS a good thing that you couldn't hack it well enough that you got out of their clutches.