As I read it, Mr Lammy has put the phrase will of the people' in inverted commas, because he does not believe it to be the will of the people, in actual terms.
That is a view, to which he is entitled, but he should have expressed himself far more clearly.
If you are an MP using social media, then you need to make sure that nothing you say can be misinterpreted, because there are lots of people put there ready to misinterpret, and hang you out to dry for your careless expression of your position