I went to see Phoenix in the tent at Reading in 2013 while Biffy Clyro headlined the main stage. Pretty much the same as how you described haha. Great set though, as always.
the hate won't matter, unless it affects sales. I can't see this announcement causing much of a rush for ticket's, but they've apparently sold a sh*t load of early birds and U21s already. I think it was probably their strategy all along.