Keynesian economics = socialism?

The so-called Keynesian economics are probably what we could call "mainstream" economics today. At some point this will have to change, since Keynesian economics are the economics of destruction. But how did they become so popular? Henry Hazlitt had a theory (on page 287 in his Failure of the 'New Economics'):

It is more instructive to inquire why Keynes put forward this extremely complicated and implausible theory. And here we may have to answer that, siding as he did with the immemorial  labor-union insistence that employment is not caused by excessive wage-rates, he had to come up with some theory as to what does cause it. And as he couldn't blame the labor-union leaders, what more natural (and politically convenient) than to blame the moneylenders, the creditors, the rich? Like Marxism, this is a class theory of the business cycle, a class theory of unemployment. As in Marxism, the capitalists become the scapegoats, with the sole difference that the chief villains are the moneylenders rather than the employers.
And that, I suspect, rather than any new discoveries of technical analysis, is the real secret of the tremendous vogue of the General Theory. It is the twentieth century's Das Kapital.

I find this very plausible. The Keynesian "system" is socialism in disguise, and socialists like disguises.