The downgrade by Macquarie Research is based on several factors that could negatively impact Disney's stock in the short term. The deteriorating linear networks, which account for a significant portion of Disney's revenue and operating income, are a major concern. Additionally, the Direct-to-Consumer strategy is still a work in progress, and the slowing growth in the Parks segment adds to the headwinds. These factors combined make it likely that the stock price will be negatively impacted in the short term.