That the mistakes in the PT stand out to myself, and others, more than in the OT or RO or TFA. All films have problems, but some are more apparent than others or more bothersome to people than others.Yeah . . . just as he has to take the flak for the poor ideas, poor execution and other mistakes in the Original Trilogy. Or Abrams has to take the flak for his mistakes and poor decisions in "The Force Awakens". Gareth Edwards has to do the same for "Rogue One". What's your point?
The PT is a bit unique in that Lucas really had sole control of the final product, versus the OT, with others having influence as well, including other directors. So, there are several factors that influence opinions on the PT, not just blind hatred.