Oh, good question! Both of those explanations make sense, or maybe Changcheng commented on the likeness, and Chu Shuzhi decided it was presumptuous or disrespectful or something for him to keep wearing the hood, if it made people draw that connection?

Every time I watch this episode I long for more meetings between Chu Shuzhi and Hei Pao Shi

They're so good! Do they only meet twice? The only other one I can think of is at the end of episode 4.