It's simple, If I don't indent properly - I don't get to run my code in python.
Yes, I know I can make my code look cleaner in Ruby, but I'm lazy. Call me shallow, but sometimes not having to type in blocks and "end" is kind of nice because of the inherent indentation constraint. And that indentation makes it easier to find lexical scope hierarchy easily too (at least for me). YMMV :-)
It's just a trade-off. You get cleaner-looking code, which is much trickier to copy off a random web page. The latter might seem trivial, but it's not so simple. In an environment with ubiquitous browsers, many programmers start as copy-pasters. (Just as many of us of earlier generations started out in BASIC.)
The programmers should hone their tools first, as they are going to be the most important part of their experience. For copy-pasting code, in vim -- surely other editors have similar, highlight the new code (and surrounding code) and hit "=" (equals) key.
If you're trying to copy a non-trivial amount of code from a web page, you're doing it wrong. In 2010, I think sharing code over the internet is a solved problem.
Newbies often try to "do it wrong." I also wrote lots of really horrendous BASIC. It was a learning experience. If you think of tab-soup as a Python newbie right of passage, that's your prerogative.
I think the point of Python's horrible syntax is to make operator overloading so painful that you're less likely to abuse it (cough C++ cough Haskell). Either that or Guido really likes underscores.