It's easy to understand what's wrong with having a founding father who was an extremist and a moron at best.
Founding fathers have a strange influence on the political discourse of a nation for as long as it lives. They set precedence for many policies that last decades if not centuries. As the founding father of PRC or CPC's supreme, Mao has made several of his decisions giving no regard for human life or dignity. His ways have made CPC into a cult and Chinese population a subject to CPC.
Now, A nation which tolerates a party that treats it's own people as mere subjects and subjects it to propaganda against the west to ingrain a false sense of enmity deserves no respect.
Slogans like 'stability of china for all it's problems, at any cost' might sound patriotic to you but are mere endorsement of open suppression of dissent and are quite scary for most people.