That's not true, Rafale has the vastly superior EWS with far more sensors and jamming capability than any of the US teen series, which is why export customers tend to upgrade F16s or F15s with Israeli stuff if possible. The manuverability is also a clear advantage, by design, the higher TWR or the lower wingloading. Add the A2A weaponry, that gives a clear edge of European missiles over US once and you know that the F18 doesn't stand a chance in a 1 on 1 comprison.
However, with the latest Block 3 upgrade, the F18 adds at least some fields where it has advantages (cockpit, CFTs, maybe AESA depending on the upgrades) and it still comes clearly cheaper, with a flyaway cost advantage of around 20 million, besides the fact that it's more suitable to Indian carriers in size as well.