On 2012-10-27 22:44 (GMT+0100) Lisi Reisz composed:

As to the original question why you can't change the default: it's FOSS. 
Either it disappeared or got hidden by accident and no one noticed, or no one 
ever got around to providing the option in the first place. Be thankful you 
have Trinity and KMail3 instead of being stuck with an unsupported old 
version, KDE4, or something worse. :-)

> What are the two blank lines for in your interpretation?

What blank lines? What "interpretation"?

> Why should it be easier to interleave starting from the top than from the
> bottom?

I can't imagine myself doing it upside down, but I should think similarly as 
for reading[1]:

Because it breaks the logical typical sequence of formulating a response, 
start to finish, instead of upside down or back to front.

Naturally anyone can start anywhere they please in any competent email 
composition window, but people do tend to start things at the beginning more 
often than at the end or in the middle, making top a quite logical default 
even if the many clueless take as an inducement to start composing without 
doing any culling, or even thinking, about what they are doing or where they are.

[1]
A: Because it breaks the logical sequence of the discussion.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
-- 
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

  Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/