I was banned from a Reddit forum for asking this question. No malice was intended and none could be inferred. Under Corbyn's leadership the UK adopted many left wing policies. These were offensive to many older Labour voters. Sanders is a more savvy politician than Corbyn, and no-one can accuse him of anti-Semitism. But having Sanders as the Democrat nominee raises the parallels between the two of them. There is the danger that not only will the Dems lose the Presidential but they could have their brand effected too.