Based on the information provided, what was the controversy surrounding the 2021 Abu Dhabi Grand Prix?

While there was a lot of complexity based on the circumstances that occurred, the prevailing controversy with the race was related to the fact that lapped cars were only partially allowed to clear the track. This meant that Max Verstappen was cleared to attack Lewis Hamilton on fresher tyres for the last part of the final lap. Lewis and Max both needed to win the final race to win the championship. This would have been Max's first ever championship or Lewis' record-breaking 8th championship. By allowing only the cars between Max and Lewis, the race director only partially adhered to the rules. This virtually handed the win to Max and Red Bull. While Mercedes immediately protested the decision and final result. Max was awarded the championship.