Yeah, JWs and most Christians miss the entire POINT of the story by focusing on what are essentially minor and irrelevant trivial details (like tar, etc, which are easily excused by "God Dun It" miraculous claims). As a result of focusing on the minor details, they're completely missing the forest for the trees (cynics might say it's intentional, designed to discourage free-thinking and rationality, allowing them to abuse the Bible passages for other purposes).
The POINT of the flood story is to demonstrate YHWH's SOLUTION to the problem of "evil men" that existed before the Flood. God's solution was not confined to the most obvious first step (wiping out evil humans), but the OTHER TWO steps that followed:
1) prohibiting bloodshed of other living beings, and
2) delegating Divine authority to mankind to enforce rule #1,
That was God's solution to address the problem of murder/manslaughter which supposedly existed BEFORE the Flood.
The reason JW's don't want people to know the real point of the story is that a proper reading opens a can of worms (questions) that are uncomfortable to answer (eg "why didn't God tell men NOT to murder each other BEFORE the Flood?" It also disproves the Christian claim that Noah offered salvation to humans before the Flood, since offering an opportunity for repentence and salvation that wasn't actually a part of the solution God implemented in the Flood account).
I wrote articles on it:
http://awgue.weebly.com/genesis-vs-2nd-peter-noah-didnt-preach-bupkis.html
http://awgue.weebly.com/does-jehovahs-witnesses-blood-policy-reflect-they-understand-noahs-flood.html
Adamah