Keynesian economics is a horrible system, but so far it works the best until we have another implemented
Keynesian economics is not science, it's just form of propaganda. You receive money from government to justify big government and call this economics, ecology etc.
So you mean the Keynesian economics is not exactly as what they said because they're under control of the goverment?
Well if your income are 100% depended on the government you wouldn't say anything to harm it. You don't bite the hand that feeds you. And that alone is enough to really be cautious about information coming from that source.
Also the only modern active alternative school is austrian and they are proven to predict things way better and they have a radically different approach(and the one that actually makes some logical sense).
These are unfair and incorrect views of the Keynesian economics.
Keynes pioneered the study of the economy as an aggregate. It also introduces the idea of disequilibrium and price stickiness, which are occurring themes if you conduct any serious macroeconomic analysis. He also introduced behavioral elements in his formal analysis e.g. money demand equation and term "Animal Spirit". He would have incorporated expectation but the mathematics at his time was not advanced enough to handle that.
The policy prescriptions from Keynes's theory are natural implications of his theory, which remains revolutionary even to this day. The great depression in the late 20s dealt a huge blow to the Austrian school as well as western capitalism in general. It beckoned a response outside the box and Keynes' demand management really was the answer until the 70s. You have to remember that even liberals in the west placed a lot of hope on Communism during the great depression, the vibe was certainly very different from now.
While it is unfortunate that Keynesian economic theories have been politicized to benefit the state power, it is also nature that for a long period of human history big states and institutions exist. The Austrian school was too ahead in its time and the technology was not there until more than a hundred years later. The free market is still an imperfect institution (as correctly realized by Keynes) that is not really free and transparent, central authority is needed to enforce property rights.
So contrary to what you have said, it is Keynesian economics that was radical to the traditional Austrian school. Hell, it is even radical in this day as the neo-liberalism (a politicized descendant of the Austrian School) took over the world from the 90s that led to the tremendous growth of wealth and income inequality.