Complex sentence: While the right-wing or conservative newspapers are not too concerned about the manifesto, "Harian Rakjat" had been come forward into the manifesto's propaganda mouthpiece, anti-imperialist, and considered the right-wing newspapers have insulted Soekarno for not supporting the manifesto.
Split into simpler sentences: While the right-wing or conservative newspapers were not too concerned about the manifesto, "Harian Rakjat" became the manifesto's propaganda mouthpiece. It remained anti-imperialist, and considered the right-wing newspapers to have insulted Sukarno for not supporting the manifesto.