Why would the command of incompatible blood head to haemolysis?

Why would the command of incompatible blood head to haemolysis?
Blood types are determined by specific proteins that are on the outside of red blood cells. As our immune system develops, we develop antibodies against adjectives proteins that are not already known to be surrounded by our bodies.
So, if I'm Type B, when my immune system develops, it will note that I own plenty of Type B blood proteins floating around and it will not form antibodies against them. It, will, however, form antibodies against Type A blood proteins since I haven't got any.
If, later, 20 years later, I'm given a transfusion of Type A blood, my own antibodies will certify the Type A cells as "foreign" and will attack them and verbs the cells (haemolysis).
Haemolytic transfusion reaction occur when the antibodies contained by the recipient patients blood react against the antigens in the donor’s blood which results contained by rapid intravascular haemolysis. This occur because of ABO incompatibility. This then cause haemoglobinuria, Haemoglbinemia, disseminated intravascular coagulation, renal failure and cardiovascular collapse.