A lot of the issues with "allies" is people wanting a pat on the back for being awesome and special because they don't hate us. Um, no, that's called not being a disgusting waste of flesh you sack of crap.
Of course there are genuine allies who actually try to help make things better and stand up for us, but often the most vocal and noticable are the ones who disappear when things get tough or are quick to remind us of how lucky we are that they accept us.

The tumblr war against allies was kicked off by an initiative of a group to get one week of LGBT moth designated as "allies week", which annoyed a lot of people for reasons.