I wholeheartedly disagree, and it is this that is what I think is the biggest problem the Labour party has at the moment. The job of a political party is to represent a set of moral and political values that are held by its members and voters. If it proves that one of those policies isn't held by the majority of the public, they shouldn't abandon that policy (providing its members still support it) - they should be doing their best to persuade the rest of the public to what they see as the correct view.
If you cast your mind back 40 years, there was a feeling that Thatcher's views were a bit extreme for the electorate and the party had made a mistake in not voting in that nice moderate Willie Whitelaw. Thatcher set about persuading people her views were right and - whether you agree with her not - she didn't leave anyone in any doubt as where she stood.
Corbyn could have the same effect, who knows. I just think this idea of governing by focus groups and soundbites has had its day