This specific part is bogus. Almost all new theories face stiff resistance from the old school.
That's apples and oranges. "Resistance" is not "suppression".
Yes, radical new ideas will face initial "show me" skepticism -- which is as it should be.
That's not at all the same thing as the crank's eternal cry that his work is being rejected/ignored because the "establishment" is working as a conspiracy to "suppress the truth" -- as opposed to the more likely explanation that it's being rejected/ignored because it's nonsense and almost everyone can see that but the crank who has too much time/emotion/ego invested in it.
Actually, point two should include the fact that junk scientists invariably refuse to reveal the details of their inventions, lest they be stolen -- denying themselves the only opportunity to benefit from their discovery through patent or historical credit. I mean, how could General Motors or even the CIA put the toothpaste back in the tube after it was published on the internet?