Haven't done a dinosaur queue in a while. And well, they named it Dreadnoughtus schrani. I mean, come on. It's a dinosaur that weighed 65 tons, it's one of the most complete Titanosaur skeletons ever found, and it has a name that immediately made me think of one of the cooler of all warrior sets. So yeah, the video above explains how amazing this find was, how it's changing what we know about these truly massive dinosaurs, and most importantly it weighed more than a 737. Just think about that for a second. A full grown Dreadnoughtus could squash an elephant under one foot and barely notice it. The heaviest estimate for Giganotosaurus is 13.8 tons, which means it would be like a moose getting attacked by a house cat.
Anyway, let's get on with the questions.
Why do people think that they deserve (or you owe them) your Battle-tag just because you've been polite and friendly in guild or chat or where-ever? I try to be that all the time, but I'm not comfortable giving out my Blizzard identity (what Battle-tags essentially are) to others whom I don't really know.
With the rise of addons like oQueue, people have gotten used to just handing their Battletags out. It's an essential part of cross-server random group forming in order to PuG content like Siege of Orgrimmar or the August Celestials/Ordos. As a result, for many people, the Battletag has become essentially just the same as being friended in game, and they don't really consider how it extends to other Blizzard games - such as Starcraft 2 or Diablo III or Hearthstone. There are all sorts of privacy concerns that not every player is comfortable with when dealing with the Battletag system.
I only accept Battletag exchange requests from people I know I like playing with enough to be grouped with them multiple times, so I relate to your discomfort. Not all players understand how personal this can feel to us, however. For people who've grown comfortable with random cross-realm grouping, it may not even seem like an issue.