Mencius once told us: competition and difficulties make you prosperous, safety and comfort make you perish(生于忧患,死于安乐).
Any country, nation or political party needs competitors, otherwise it will perish like the Indians of the American continent.
CCP has never stopped factional struggle from the moment it was born. For example, the struggle between the Comintern faction Wang Ming&Bogu and the local faction Mao Zedong&Zhu De. This is not a secret, but history written into history textbooks.
After 1949, Communist countries demanded the dictatorship of the proletariat and established a one party state. Except CCP, other parties are opposition parties that can only conduct political consultation. If CCP prohibits inner-party competition, CCP will perish.