They have, and they voted to Leave. I voted Remain but if 'we' had won and Leave voters were out protesting everyone on here would be saying you had a vote and lost, that's democracy, we need to move on etc. Believe me I think it's a shocking decision by the public and can't believe we're leaving, but we voted and that's what most people wanted. How we leave is a different matter, but the upshot is we're leaving.
Do you? More people voted to Leave than Remain, so we're leaving.
They voted for £350M extra for the NHS each week. They voted for less immigration. They voted for miracle trade deals with the non-EU world that would boost the economy, despite there being no supporting evidence such deals were feasible, they voted for leaving but retaining full access to the single market.
All of which the "Government" have rowed furiously backward on. The people were presented the prospect of an impossible deal by a Leave camp largely free from the shackles of actually having to deliver on those promises.
The final deal will look very different to the promises that the Leave vote won with. It is gross revisionism to even suggest that the current proposed Hard Brexit with a cliff edge was on the cards last June.
Triggering Article 50 discharges the obligation to the referendum result. In two years time, parliament still needs to ask, "Is this deal better than revoking Article 50?". If the deal is as bad as we fear, Parliament needs to grow enough of a spine to ask the electorate if they want to accept that deal. A 2nd referendum on the precise terms of the deal should be achievable, there are enough remain Tory MPs, and it is not an outright rejection.