“I will do whatever it takes to stop Brexit.” From that pledge by Jo Swinson, in her first hour as leader of the Liberal Democrats, we know what “liberalism” now means. It means rejecting the democratically expressed wishes of the majority in a referendum. It means seeking to implement the preferences of a defeated establishment minority at the expense of the majority will of the electorate.
There is absolutely no moral or qualitative difference between repudiating the result of the 2016 EU referendum and blocking the outcome of the 1945 general election, or the 1979 election, or any other legally recorded consequence of a government going to the country at a moment of historic significance. You either accept the democratic verdict produced by universal suffrage, or you don’t.
If you do not, there may be persuasive philosophical reasons why you think mass democracy is a bad idea. In that case, you have a perfect right to advance that view; but do not simultaneously feign adherence to the current system and, above all, do not insult the public’s intelligence by calling yourself a “liberal”.