I think it's exaggerated. A lot of scary hype attached to it because risk of bricking is minimal but consequences of bricking are catastrophic.
If you follow all instructions carefully then it is almost nonexistent. The rooting/hack tools always specify what has been tested, what is untested, what is known, what is still unknown, what is not recommended, what to expect, and how to recover from unexpected faults.
Most bricks can be recovered through softwares. There's always the option of doing a nuke and pave "rewrite" of clean stock firmware. If you read the xda forums you'll see that these experimenters routinely brick and unbrick devices - they are confronted by a permanently dead, irrecoverable, unsalvageable device very rarely.