yes, because they are the opposition, they are against everything mays government does. thats one of the issues with a 2 party system.
there are people in both parties who are against the brexit. its a stupid idea marketed by idiot populists like boris johnson who are obviously only in it to advance their political career and they dont give a fuck about how much its going to cost. of course people will vote leave if they are not given accurate information. brexiteers like johnson just magically made up that leaving the eu would save the UK billions, which is definitely not true, and the british people were stupid enough to believe it.
we will all see the british government get fucked, they will get crushed between the EU which doesnt want to give an inch, and their impossible brexit promises.
after the government is shown to be incapable of managing the process, either the brits get a bad deal, or no deal, and both will cost them a lot of money and opportunities compared to the scenario where they stayed in the EU.