Again, as and when the UK leaves, the EU will be sad about it. Why this insistence that the EU might "happily wave us goodbye" emerges is anyone's guess.
The EU would clearly prefer us to stay in. They've said so several times. But it's not inconsistent with that to say, as they also have done, that they are prepared for us to leave, once we get around to agreeing on how to achieve that. And they are prepared for No Deal.
As to what Juncker said before the campaign -- well, he was stupid for putting it that way. Better had he stuck to saying that "If the UK wants to leave then the EU will be sad about it, but withdrawal negotiations will be inevitably be shaped by the EU's desire to discourage other nations from leaving."
Although having said that, as far as I can see, Juncker didn't actually say it in that explicit way, and it's a media invention.
A more accurate rendering of the quote is something like: “The United Kingdom will have to accept being regarded as a third country, which won’t be handled with kid gloves. If the British leave Europe, people will have to face the consequences — we will have to, just as they will. It’s not a threat but our relations will no longer be what they are today.”