Haemophilia was known to be hereditary very early, even if this disease has a complex transmission pattern, from mothers to sons. Wikipedia says it was already known from the ancient Hebrews who didn't circumcise sons of women who had this kind of "tendency to bleed" in their family.
It was called a royal disease in some countries, because some royal families carried the guilty gene.
But the etymology doesn't say anything about the hereditary side.
There's a confusion in the etymology meaning, very often with the "philia" part, which a lot of people learned in school to mean "to like/to love" (friendship as in "Philippos", the horses' friend, the horses lover.), when there's an additional meaning "a tendency to", as you've said.
So, it explains the apparent auto-antonymy in "pedophilia" too, that is surely not a love for young children, but rather a pathological tendency.
So, it's absolutely not "humans who love blood undeniably wouldn't want to lose it",
and the etymology is logical.
To be fair, Haemophilia is not a pathological "tendency" to bleed, it's a blood disease. There is no tendency to bleed, but big difficulties to stop the bleedings, even the small ones, when they occur. Because they lack of some blood factors responsible of the blood coagulation.
As there is no change in the meaning, the Typology of Blank doesn't apply, there is no semantic change, only a lack of Greek teaching in schools, and people forget the etymology of words.
