Exchange sites by default should not be trusted no matter how much reputation they have garnered over the years and this big names have not stopped in ensuing that their trust is being ridiculed by those who have invested trust in them though. The issue around here is that until there are decentralised exchange sites, this issue will  continue to be a reoccurring issue.

For the pumping of bitcoin, I don't think the credit should be given to Bitfinex alone because even though they might be large, they don't define what happen in the entire crypto market. The market is very much larger than what they could control in my opinion.