I agree the Elemental Resistances list should logically fall under the Resistance tab. However...

... I can see why the dev. team opted to place it under Attributes tab as it makes for a rather balanced, two-column layout with a 6-3-2-row segments. Imagine pulling Elemental Resistances out, this would cause a huge gap that would require the other lists to fill its place. This would then perhaps cause more imbalance, aesthetically speaking...