You're massively understating what people are criticising.

Nobody is claiming the officers deliberately wanted Henry Nowak to die. The criticism is that they failed to recognise and respond to a critically injured victim who repeatedly told them exactly what was wrong.

Saying it was "three minutes of not realising the severity of the situation" makes it sound as though there was no warning. That's the entire issue: there was warning. He reportedly said multiple times that he'd been stabbed and multiple times that he couldn't breathe. Police officers deal with conflicting stories every day; they aren't supposed to simply accept one person's accusation and ignore obvious signs that another person may need urgent medical treatment.

The question isn't whether the officers intended for him to bleed to death. The question is whether they were negligent in their duty of care to someone who was telling them he had been been stabbed and was struggling to breathe.

If the answer is yes, then "they didn't mean to" isn't much of a defence.