Lith had reached top 10,000 but his goal was to be in the top class. He had thought to be at the bottom of the class but after he heard Liam trash talking to him mid fight, he had a thought which made him understand that getting bullied or trash talked was inevitable as long as he was the weaker one.
He had thought of pretending to be weak and faceslap people later, as mentioned in novels that he used to read back on Earth but reality was different. Just a few words from his opponent was enough to let him know that to get trash talked or bullied was very annoying. Yes, he may get to faceslap later but he had to endure the humiliation that was brought before.