I respectfully disagree, however intentional, its a bug.
"
A software bug is the common term used to describe an error, flaw, mistake, failure, or fault in a computer program or system that produces an incorrect or unexpected result, or causes it to behave in unintended ways."
Source Wiki Pedia http://en.wikipedia.org/wiki/Software_bug
In this case the defintion fits the program flaw, error, mistake, failure and fault of the programers.
Even well intentioned software by design can contain a flaw, error, mistake, failure or fault. Currently it would appear that all of these items are in fact present in the program, BY DESIGN.
It's a bug. It needs to be fixed. Plain and simple.
And please do not direct me to send feedback to apple again. That is what I am doing by posting this here, on an apple discussion list that the apple engineers that work on mail.app are fully aware of.
Let's get a fix.