Will Biden Calling Trump And MAGA Losers And Garbage Hurt Harris?

Of course, it will. To put it mildly, it was not helpful for Harris. Biden's approval rating is at 40% so the downside will be limited. It's already baked into the cake that most Americans have soured on Biden. That's why he's not the nominee. 

Biden won't get any gold star for being intellectually honest. Far from it. This was the last thing Harris needed to dent her momentum, which mostly is unseen but definitely in her sails. So, Joe will cause some damage in support but it will be more on the margins. If this election was really neck and neck, it could cost Harris the presidency but in reality, Harris has the Big Mo, whether MAGA and others want to believe it or not. 

Again, politely put, it was not helpful but par for the course where Joe is concerned. Biden has put his foot in his mouth more times than I can count in his career. Joe is Joe, we'll just have to live with whatever damage he caused with those comments.