From the BBC:
Conservative MP Nigel Evans says, "the British people have voted to leave the European Union [in the 2016 referendum]. If this Parliament decides we are not going to leave the European Union, then the British people ought to have an opportunity to change their Parliament."
This argument may have been all very well in late 2016 or early 2017, but the current parliament was elected more recently than the referendum - that is, voters have already had one chance to change their parliament.
If the outcome of the 2017 election seems to conflict with that of the 2016 referendum, then perhaps the more recent should take precedence. At the very least, there's as much case for re-running the 2016 referendum as there is for re-running the 2017 general election.