King Elrond?

[Tar Elenion]

But isn't there a diffrence between 'ruling over' something and actually being King, is there not?

It goes to show that there does not seem to be an aversion among the Elves to accepting someone who is partly or fully human as their lord.
The most explicit statement we have regarding how the kingship over the Noldor should pass (though not all agreed) comes from Maedhros:
"For Maedhros begged forgiveness for the desertion in Araman; and he waived his claim to kingship over all the Noldor, saying to Fingolfin: 'If there lay no grievance between us, lord, still the kingship would rightly come to you, the eldest here of the house of Finwë, and not the least wise.'"