Does being censored mean David Icke was onto something?

They’re separate questions. If someone’s views are restricted or dismissed, that can raise a fair question about how the decision was made. It doesn’t show that their claims are true. I’d look at the evidence for each claim on its own, rather than treating the reaction to the person as proof either way.

It helps to be specific about what “censorship” means in a given claim. Criticism, a private organization choosing not to host someone, and government suppression are different situations. Without knowing which event is being discussed and what evidence supports the account, it’s hard to draw much from the label alone.

Don’t let either side do your thinking for you. A person being mocked doesn’t make them wrong, and a person being restricted doesn’t make them right. Pick one concrete claim, check what evidence would support or undermine it, and see whether the explanation can be tested independently.