Ah, that old chestnut again. The desire to leave the EU was/is spreads right across the political spectrum, left as well as right. That's why great swathes of Labour heartlands voted for leave.Well of course they're different. JC's supporters are left of centre and the Leavers are (mainly) right of centre but the point is that both are at odds with their MPs.
JC's supporters (those that are genuine JC supporters, not just mischief makers) are left wing, of course.