教室里传来一阵激烈的掌声

As this old man is the leader of the Qing Gang, Ji Feng is naturally very polite to him. Luo Xun is Luo Xun, and the Qinggang is the Qinggang. These are two different things. Ji Feng will not have a bad feeling for the entire Qinggang just because of Luo Xun....