Yes, the sentence you provided can be rephrased for clarity or style. Here's one possible rephrasing:
"Are you all upset about his outfit choice? The engagement on this post is quite low."
The original sentence means the speaker is asking if the audience (referred to as "y'all") feels offended or upset by someone's choice of clothing. Additionally, the speaker notes that the interaction (likes, comments, shares, etc.) on the social media post