One should not think that the fundamental scientific knowledge can be harmful.
Most of theoretical physicists adequately reflects the physical reality and forms the basis of our knowledge of nature.
However,some physical theories arised in the twentieth century
are not supported by experimental data.
At the same time impression of their credibility masked by a very complex mathematical apparatus is so great that some of them are even awarded the Nobel Prize.
However, the fact it does not change - a number of generally accepted theories created in the twentieth century are not supported by the experience and therefore should be recognized as pseudoscientific and harmful.