The propaganda/evil conspiracy angle is unconvincing here. More likely it's not propaganda, but facts and science, and it replaced centuries-old science because it is better and more accurate.
For example, do you also believe there is 'propaganda that geocentrism is a pseudoscience, so successfully drilled into people over the decades that they have never been to a geocentric astronomer, nor do they know of anyone who has"?
Or maybe we just improved our science a bit in the last several hundred years?