I've encountered and used em dashes regularly for the last 20 years. If most of your reading and writing are associated with social media, I could see the trend

I've encountered and used em dashes regularly for the last 20 years. If most of your reading and writing are associated with social media, I could see the trend you're describing appearing real within that limited context. But em dashes are not new and have been a feature of high quality writing for many decades.