Re: Can someone please explain...
Not to nitpick (well actually...) but since when was Corbyn a union leader? If you want to criticise unions here in the UK, you don't need a straw-man argument. Let's start with the brexiter* Len McCluskey instead, and the unreasonable power he seems to wield in the Labour Party without (seemingly) appropriate responsiblities to reflect the opinions or interests of his union members. No need to invoke Corbyn, whose faults lie elsewhere (principally in being a rubbish opposition leader when it comes to actually holding government to account).
*brexit certainly isn't going to improve the lot of union members despite the myriad hollow promises that have been made in its name. Removal (or the possibility of removal) of the strong employment rights gained through EU membership is the start of the slippery slope.