The problem is that many of their voters are simple folk who actually think that the Greens may 'have some answers' to ecological problems and barely notice their horrific political leanings which make Jeremy look like a mega rightist. Even when they are right - they are wrong.
Hosts of former British Communist Party members fled to the Greens many moons ago. Their influence has been significant.
Water melons - 'Green on the outside, red in the middle!'