> It just turns it into an obvious statement and doesn't convey what the article is about, which is about their life, training, etc.

It's not an obvious statement.

It tells us that the gladiators aimed to entertain the masses. It could have been that they didn't care about their audience (and only cared about money, or saving their lives). Or it could be that they had contempt for their audience (if they for example were forced to fight against their will). It could also have been that they lived to entertain the elites and not the masses. Or lived to entertain other gladiators, or please the gods or any other alternatives.