They think it's great because, in a tragic case of hilarity, jumping into code with minimal design is what python is great at.
We think it's great because, among other things, it has first-class functions and a very high code:boilerplate ratio. This lets us write very concise, readable, and maintainable code.
Eww, no. I've never seen good Python code that asserts types because it's not the idiom for you to care. For instance, suppose you write a function like:
def get_contents_of(obj): return obj.read()
In this case, obj might be a file, or a web request, or a string (via the StringIO interface). Who knows? Who cares? As long as obj.read returns something, it works. BTW, this is supremely nice for unit testing when you don't really want to hit an SQL server 1,000 times in a tight loop.
Now, you could write something like assert isinstance(obj, file) to guarantee that you're only dealing with file objects. Of course, that lays waste to the whole concept of duck typing and people will laugh at you for doing it. So dropping that bad idea, you could write assert hasattr(obj, 'read') to ensure that the object has the needed methods. But why? Python gives you that check for free when you try to call the method. Let it do the heavy lifting and concentrate on the parts of the problem you actually care about.
Exceptions are one of the worst things to have become common - an "error" is almost always only caught outside the scope that it occurred in, hence the stack has already been unwound and thus there is no sane way to fix the error and retry the operation that caused the exception.
Yeah, that would be terrible. You almost never use them in Python like that, partially because Python tends to have a vastly shallower call stack than, say, Java (largely because you don't need 10 layers of abstraction between bits of code thanks to the duck typing we just talked about).
I think it boils down to you not knowing idiomatic Python. That's OK. I'm ignorant about lots of things, too. But I think you'd find that you enjoy it more if you stop trying to write C or Java in Python, because that almost never works out well.