I don't know what on earth you are on about, but quite simply there are a large chunk of remain voters who want parliament to prevent the UK leaving the EU, despite the vote for leave in the referendum. Not many of these people vote Tory, quite a few vote Labour. Therefore many of these people will be quite annoyed if the Labour party doesn't vote against triggering article 50. On the other hand if Labour do vote against triggering article 50 then it will annoy an awful lot of other Labour voters and will be seen quite correctly as an attempt to prevent the implementation of the referendum result.