Wow, thank you for that information about Marx. For anyone else in the thread, here's the source:
https://www.marxists.org/archive/marx/works/1873/01/indifferentism.htm
It cannot be denied that if the apostles of political indifferentism were to express themselves with such clarity, the working class would make short shrift of them and would resent being insulted by these doctrinaire bourgeois and displaced gentlemen, who are so stupid or so naive as to attempt to deny to the working class any real means of struggle.
https://www.marxists.org/archive/marx/works/1847/communist-league/1850-ad1.htm
The relationship of the revolutionary workers’ party to the petty-bourgeois democrats is this: it cooperates with them against the party which they aim to overthrow; it opposes them wherever they wish to secure their own position.
the workers, and above all the League, must work for the creation of an independent organization of the workers’ party, both secret and open, and alongside the official democrats, and the League must aim to make every one of its communes a center and nucleus of workers’ associations in which the position and interests of the proletariat can be discussed free from bourgeois influence.
