All I can say is that I've had an account (which I've been active on) since the site opened and I've never heard of a case of a DW user being censored by the site owners. And given that in its early years there were many people who felt they had to take a side of being pro-DW or pro-LiveJournal, and were thus looking for things to complain about, I feel fairly sure I would have had it been an issue.