Because it's Metallica!
Yeah, I'm one of those bitter bastards that thinks Metallica gave up on their roots and sold out when they released the Black Album and started suing their fans for use of Napster, even thought tape trading (aka "Music Piracy") is why the band formed and (according to Lars Ulrich) how the band got big. So I'm enjoying some schadenfreude about this, which I'm sure they can't give a crap about as they are one of the biggest bands on the planet and will cry into their money and acclaim to just carry on regardless.
They are one of the most respected and loved bands in heavy metal (BASTARDS!) so I can't see them giving much of a crap about this poll. It could be 99% for all they care and they would still turn up, do their thing incredibly well, and then head off to another gig full of people that like them and not give a rats arse. Even though a lot of people, including people outside of the metal world, do like them (ref The Black Album onwards) and will be more than happy to lose their shit to Enter Sandman and "that one from Mission Impossible". A bunch of pseduo-hippy accountants are acting like one act is going to kill their buzz, even though it's going to get people moving and loving a bit of the old guitar action when they actually hear it . But even then it doesn't matter....
Because it's Glastonbury
Take a guess how many metal bands have already played Glastonbury. If your answer was more than "none, ever" then you're wrong, and you're missing the point of why they were booked. This is a wild card booking, an attempt to mix things up. They were always going to go down like a bucket of sick because this is not a metal event. But it's an event with 100+ acts (so people are reacting to one act on the bill), covering a wild range of tastes, so anyone complaining about something a bit left field turning up is missing the point. And the point is: Michael Eavis doesn't give a fuck. Never has, never will (one of the reasons I like him). The event is run like no other, mostly him going "oooh, I wonder who I want to book this year" and making a couple of phone calls. My money says he wanted to get some edge going with this booking AND he likes the band.
And when I say "like no other" I'm leading onto my key point....
And when I say "like no other" I'm leading onto my key point....
The Survey Was Done By A Ticket Company
Yeah, it's all about the money. Viagogo (and others) are pissed because the Glastonbury ticket buying process is "buy on spec, and then not be able to resell your ticket once the headlines are announced". You know, like through a ticket sales company like.... Viagogo! They can't make money off of Glastonbury, and this sticks in their craw. So they get some bullshit survey done to try and make the re-selling of the tickets sound like a good plan. But that won't work, because Michael Eavis. This is a pure marketing tactic, a total money grab. There is no scandal, just a bunch of ticket scalps who want to force Glastonbury into changing its ticket policy.
So this isn't about the act (who people will enjoy) and it isn't about some weird "no one but metal heads likes one of the most accessible metal acts of the last 20 years" thing. It's about wanting to re-sell tickets and make some money. Which is totally not a Glastonbury thing, so frankly anyone moaning about it can shut up. Unless they ask to hear something from "Kill 'Em All", in which case they should be let loose on the PA all night long.