"If facebook started banning and censoring people who posted links to external content... it would be ridiculous. Why then are there so many who against using non-personal information to post on steemit?

It's funny because this is exactly what has happened to a poster here called @masteryoda.
That analogy seems pretty sensational, in that nobody censored or deleted his posts. So definitely not "exactly what happened" here. The way I read it he was unhappy (with reason IMHO) with the voting response by a group of voters to his posts and decided it wasn't enjoyable to post the content he had previously enjoyed posting here and thus announced he was taking his ball (previously posted content) and going home as is his right. Fortunately the community rallied behind him or at least showed support of his post and the resulting discussion and he was shown some steem-y love, the best kind!