As noted, "we always talk about" these things. Unless I've heard it first hand or as an interpretation from the NUS, I try not to talk about what other people were thinking when enacting a rule or code.
This is the benefit of attending regional or national umpire clinics or schools. Even better, the convention where the cause and effect is presented and, if necessary debated. This is where you get to the meat of the reason for a rule. Granted, as we have seen in recent posts, even member of the NUS don't get it right even if they were in the room.
The problem I have with umpires citing "intent" or "spirit" of a rule is that many are just applying their view, not necessarily that of those who provided it. Of course, if there were not differing views or opinions, the title to this board could be changed to Softball War Stories.
I had an on-going, two month debate with a local coach/player/sponsor who insisted on telling me the rule establishing a 1-1 count was a speed-up rule ASA was putting into place to get more game into the day and make more money. Even after informing him of exactly why the rule was proposed and passed, he insisted I was wrong and had no idea what I was talking about.
Then again, I've have people including umpires insisting hands are part of the bat and it has always been that way. Another point why is discount claims of knowing intent or spirt, is that many umpires know this from LL when they played and have never heard anything different in the 2-3 clinics they have attended over the past 15-20 years. It is also an easy shortcut to a discussion when that individual really doesn't know the rule and is too lazy to learn.
Does that mean it should always be discounted? Nope, because there are a lot of people out there that do know the intent or spirt and it can be really simple. It is when this "reason" is used when the rule, in black and white, is being ignored and replaced with it.