Revolutions require a critical mass of people to come together, and sometimes people who have different vision for the end goal find opportunities to work together as Bolsheviks and anarchists did. Lenin wrote extensively on the subject of when alliances should be formed. MLs don't have a problem working with anarchists, recognizing that there are common interests and that a time may come where such alliances may need to be rethought. The hate largely comes from the side of anarchists who refuse to work with MLs and spend their time trying to discredit the accomplishments of existing socialist states.
It's also worth noting that the reality in the west today is that both MLs and anarchists are an insignificant political minority. If the current system does end up collapsing in the near future, then fascism is the most likely outcome. While the left bickers, the right is rapidly growing in power in vast majority of western countries.