Sports equipment is not free with Aer Lingus, they charge £25.00 per item, per one way flight. There are plenty of advantages to flying with Aer Lingus but free sports equipment isn't one of them and neither is baggage as Aer Lingus have higher baggage charges as well.
The higher charges might not look so great for passengers but they will be an important factor for Aer Lingus at Gatwick as they make quite a bit of money from them.