I think if you guys are sure it's not the policies then fine but you absolutely cannot just blame 'the media' and Brexit, that's a sure fire route to another defeat in 5 years.
There will always be a 'Brexit' in an election, a topic the right can point to and say it's more important than social justice and inequality, always, until the end of time. And a fair proportion of the people will say that's why they voted Tory but the truth will be they don't think we need more social justice or equality, and these results prove that's not just people doing well, it's also people who are struggling.
If Labour wants to be on the left it has to do a lot more outside of the campaign window to convince people that they need what the left is offering, and it BADLY needs to happen outside towns and cities. That this Labour leadership hasn't even convinced people who would directly benefit from their polices to vote for them...it's shameful, no matter what the media is saying, what the other leaders are saying, they've done a bad job.