Q:

Are policies regarding flags too broad/vague?

In an answer to a hot meta question, a diamond moderator Brad Larson says:

Different moderators will handle flags on accepted answers
  differently, so you will see some variability there.

I've been reading meta quite a bit, and I admit, that this particular problem comes up every now and then and not only accepted answers. Some times diamond moderators have opposite opinions on an issue, and that may include a flagging issue.
Does this mean that StackOverflow policies is vague and generally not well enough defined? When one flags a question and it's a hit or miss, depending on who happens to review the flag it is somewhat disheartening and demotivating.
Can we (or whoever defines the policies) make them more clear so that the variability (almost) never happens?

A:

What it means is that thousands of authors write thousands of posts each day and... they're all a little bit different.
The problems that arise in relation to them also have quite a bit of variety.
But there are only a handful of flag types. And one catch-all, into which folks type things. Things that also have a lot of variety.
So when folks talk about policies, they're talking about guidelines that moderators (and others) attempt to apply to this dizzying kaleidoscope of flagged posts. Impressively, folks usually agree on both the problem and the nature of the solution... But there will always be cases where two people look at the post and the flag and each see something different. 
That's ok. That's why we have moderators, humans with good judgment selected by the community. They may not always agree, but you can usually trust them to make a good call and to calmly address any concerns in those rare instances when they make mistakes. 

A:

No, it means that we're human. We're not flag-handling robots who follow a precise algorithm, we make value judgments on a flag-by-flag basis.
That means that moderators will handle things in slightly different ways, or even disagree with each other. In cases where that happens, there are mechanisms for arriving at consensus on what should be done (chat conversations, Meta, votes, etc.). Few actions are irreversible.
In almost all cases, we do handle things the same way. You remember the times we don't precisely because they are so infrequent. Also, people don't come to Meta to say how happy they were that 100 of their flags were handled as they wanted.
There's very little in the way of rigid policy on these sites, and I think that's for the best. It allows us to enforce the spirit of the "law", not the letter of it. I know programmers want everything to be exact and repeatable, but the real world doesn't work that way.

