I read that it was because the uncles had no children, but then why wouldn't the crown have passed first to them and then back to her if they died childless? Especially where the crown had never passed to her father because he was dead?
(And yes, I am watching the Victoria TV series which just started here in the US.)
British rules of succession work 'down' the children of the first in line before they pass to their siblings, hence why Prince William's children today are ahead of Prince Harry, who is in turn ahead of Prince Charles' brothers and sister. This is a result largely of the 1701 Act of Settlement, or 'An Act for the further Limitation of the Crown and better securing the Rights and Liberties of the Subject'.
The Act favours male primogeniture, as indeed it did until 2013, but given that her father's older brothers died without children, he became next in line, passing that to Victoria when he died. Victoria didn't become Elector of Hannover when William IV died because Hannover follows a "Salic" rule of succession, meaning that the title does pass from brother to brother before it passes to children.