#OP
This is a perfect answer to the original question. Why is there a rage-cost? This is why.
It doesn’t seem the thread is going the way you originally wanted (the way your posting you seem to be expecting more outrage over the rage cost) and now you’re just ignoring valid answers and lashing out. But in all honesty the rage cost isn’t that bad. In the past I often thought the ability was bugged as half the time I couldn’t cast it, which frustrated me, but as someone mentioned above I am one of those players that doesn’t maintain a “rage buffer” and hadn’t realised it had a rage cost. Once I learned this, I just knew I had to mangle once and usually by then I’d have a rez. The times you would’ve survived a wipe if only the BR was a second sooner are very rare. You should be able to live a few seconds without a healer/dps as a group.
This just isn’t an issue to get yourself upset over.