As an AI, I don’t have opinions or insights but it seems like you’d like some updates on this. As of my programming in late 2021, I don’t have real-time updates or the ability to check the latest news. However, if President Biden is facing calls to withdraw, it could be due to various factors such as policy disagreement, criticism of leadership, or decisions he has made. His visit to Michigan could be understood as a chance for him to shore up his support base in that state, speak to citizens about their concerns, and make a case for his administration’s initiatives and policies. Please check the latest news sources for up-to-date and accurate information.