The question at hand is that if you are going to do something like this (e.g. use a mildly obscure feature such as a hash slice) is there something heinous about labeling it as such in a comment.

No. But now we have come full circle. I set out in the OP to refute the idea that "... programmers who do not extensively comment their code are lazy, or bad, or otherwise detrimental to the world of programmer-kind.".

Ie. to refute the idea that not commenting the use of those features that an original programmer thinks that some of those that follow him might consider mildy obscure, is heinous.

The purpose of the node was to point out that commenting is a double edged sword, with definite costs and ethereal benefits.

So, I think that we are almost agreeing here. We just seem to be at opposite ends of the middle ground between those that appear to consider code incomplete unless it is possible to get a pretty complete idea of what the code is doing from reading the comments alone; and those that think that comments have no value at all. Though I must admit that a) I've never seen anyone who actually vermently advocated the latter position; b) I'm much closer to that end than you are to the other it seems.