Harry’s not to blame, but the person Lucius believes is posing as Harry might well be.
From Lucius’s perspective it must seem more likely that Hermione is a cat’s paw than that she’s actually strong enough to beat Draco fairly. Plus, having a Muggleborn arrested for the attempted murder of another student hurts Dumbledore as well. It would be far from unreasonable for Lucius to leap to conclusions at this point.
Harry’s not to blame, but the person Lucius believes is posing as Harry might well be.
From Lucius’s perspective it must seem more likely that Hermione is a cat’s paw than that she’s actually strong enough to beat Draco fairly. Plus, having a Muggleborn arrested for the attempted murder of another student hurts Dumbledore as well. It would be far from unreasonable for Lucius to leap to conclusions at this point.