I hear what you're saying, but I made sure I was very careful in how I worded the details of the perk. The description clearly states that the primary function reduces the level of radiation caused by lightning, car explosions, and mini nukes. The bonus feature also states that it would prevent and not cause ghoulification that would otherwise be caused by the initial lightning strike. Also, in the very first paragraph, I have once again clarified that it is the radioactive lighting itself that would cause ghoulfication. Here is the full paragraph for anyone who is still confused by those who may have suggested otherwise:
"The most devastating explosions we can face in Fallout 4 are those with a nuclear source, including car explosions and mini nukes. In addition to this, we now have potentially lethal radioactive lightning to contend with, which is caused by radiation storms that blow in from the Glowing Sea. This perk protects against all of these threats by significantly reducing the amount of radiation received by the player. This is especially important due to the far more lethal effect of radiation reducing your maximum health until removed. In addition to this, the bonus feature at rank 3 will go some way to preventing you from being transformed into a ghoul by radioactive lightning. The possibility of being transformed into a ghoul has not yet been mentioned by any of the devs, but is something that I am almost certain will be added as a new feature of the franchise."
I am quite certain that there would be a fair amount of warning of incoming storms for those who would rather not take the risk, as well as 'guaranteed' locations of frequent lightning strikes (such as a very tall metallic tower) for those who would actively seek out the opportunity to play as a ghoul. As you mention in your comment, this point has already been taken into account as part of my research.
Once the game is released, if I am proved wrong with some or all of my theories, then at least I know that I have actively contributed to the fallout community with speculative ideas that many people have found interesting, as well as giving us all something to contemplate due to the lack of official information. But if I am proved right, I certainly won't be laughing at those who have criticised both my ideas and my efforts. At the end of the day, everyone is entitled to their opinion, but it takes more guts than you perhaps realise to put forward ideas in the face of strong opposition. And I would much rather be the person bold enough to attract the attention of critics that the one hiding behind a keyboard pointing and laughing.