asked me "What's up with your double standard bro?"
To be fair what he really said was: Matias; serious question — what's your opinion about Google violating Apple's HIG by using Android–like share buttons in their iOS apps?
Given all the FUD around what design guidelines are for and how designers and developers should approach them, I think it's a fair question.
Iconography is an interesting middle ground between the visual emotional and brand elements of a platform and the functional elements. Some icons have become universal, like the magnifying icon for search. Others are strongly branded, like the +1 or thumb up. Share sits in a middle ground where many consider it a brand element of their platform or service, while it is at the same time being so ubiquitous that recognition is important. There's many other "universal" icons in the HIG that popular services deviate from because they feel that their unique spin does not hamper usability and is
part of their brand. Consider the Twitter compose button with it's fanciful quill.
The share icon Google uses in it's properties (and the share icon that Android endorses) is a popular opensource icon and one that we feel well describes the connective nature of sharing. In a sense you could say we believe it's part of our brand and
that Google's brand is to embrace the open and universal standard.