We're not discussing the obvious flaws of Albus Dumbledore here, we're talking about Sirius Black's character which you seem keen on attacking even though you claim to care very little about the series or the characters??
You can't negate someone's love just because someone else loved them differently. Molly, Hagrid, and McGonagall were amazing (but also flawed in their own ways!) and they don't get nearly enough credit for how much they meant for Harry's life and his development into the man he becomes, but their love doesn't negate Sirius' love. Nor does Sirius' love for James negate his love for Harry. Love is a versatile thing that can't be boxed up into one definition or example.