For the liberals in the walls : a party isn't an opinion, or even an ideology. A party is an organisation that seek to hold power.
Inside any party on earth there is divergence in ideologies, and all liberal parties under liberal democracy are expected to have an internal democracy. So if there is democracy and plurality inside of parties, why should there necessarily be multiple parties fighting for power?
The building blocks of liberal democracy are justified by the same myth as the "free market" economics : that competition drive humanity to the best outcome in every domain. This is a capitalist lie. Politics are just like marketing, the more money you pour in the more you sell.
If you want cooperation, why putting people against each other for power by having multiple organisations trying to get it? Why not putting people in responsibility according to the wisdom of the people that are inside one power organisation? Why not having people's representation done by local elections to build an assembly of trusted people rather than marketed people?
If you truly say you are for the proletariat you have to ground yourself to materialist analysis. If you think your theory has more potential that speaks for the people better, then its better that you cooperate with the party that understood the dialectics and led the revolution instead of useless chantings that the one party isn't the way. There's a reason their revolution was successful. Do material analysis first and realize why, than focusing on ideological thinking that "there are always differences". if there are differences then there are ways to solve those differences within the party.
