It’s a genuine quote from something Marx wrote, the ending of this article from November 1848:
https://www.marxists.org/archive/marx/works/1848/11/06.htm
As can be seen, Marx was commenting on the suppression of the bourgeois revolution against feudal and dynastic rule in Austria following defeats elsewhere in Europe, all due in his opinion to the timidity, cowardice and betrayal of the bourgeoisie itself.
He was making the point that a successful bourgeois revolution to establish the rule of the capitalist class would have to do what a part of the bourgeoisie in France had done in 1793-4 under Robespierre and the others.
In other words, he was talking about the bourgeois revolution not the socialist revolution, the coming to power of the capitalist class not the working class. He was, however, in favour of a bourgeois revolution in Germany including Austria as clearing the way for a “proletarian revolution” which he expected to rapidly follow.
It didn’t of course and neither revolution occurred. Marx later recognised that he had grossly over-rated the prospects of a proletarian revolution in 1848.
In the event the capitalist class didn’t gain full control of the state in Germany and Austria until after the end, and as a consequence of the First World War. Which was a festival of bloody violence if ever there was.
Later, in the 1870s. Marx spoke of the possibility in certain countries of the working class winning control of political power via the ballot box, though he expected a “slaveholders’ revolt” against this democratic decision to end capitalism by a section of the capitalist class which would have to be suppressed.