I don't think I ever had a bug due to wrong indentation. I admit that I seldom copy-and-paste code from web pages, but even then I don't remember ever having troubles with it. By no means do I intend to invalidate your experience, just saying that I/some/a lot of people have no problems with this. When discussing Python there are some issues that regularly come up (package boilerplate, complex data model, asyncio), but the indentation isn't mentioned in my experience. I'm doing Python for 4+ years and mostly used (and still do use) C and C++ before that, and some Basics and php before that.
What I feel is very important when editing source (not just Python, any source) is to have an editor that isn't entirely bad about handling indentation. Very simple editors just delete/replace a selection when hitting tab. Slightly smarter editors prepend a tab to each line, or indent one level. Emacs knows enough about indenting things that it cycles between possible indentation levels. An editor supporting shift-tab (reverse indenting) is rather helpful.
Personally I find it easier to restructure Python code than eg. C code, because I don't have to adjust braces manually. In Python I can just move a block around and, if necessary, move it horizontally to the correct level, whereas in bracelang I often have to adjust braces as well, which are outside the moved section and need extra cursor navigation.
Pycharm, by way of it's IntelliJ heritage is pretty good here; when moving code it automatically adjusts the indentation if it is distinct (eg. move a few statements from an `if` to a upper level and it adjusts the indentation automatically to match the surrounding block, since the statements can't possibly be indented due to the lack of a if/for/while/def). CLion can do similar things. The IntelliJ IDEs do these things for any supported language, sometimes across languages (paste some Java code into a Kotlin file - IntelliJ will automatically translate it into Kotlin, adjust the code style and sometimes even rename variables by type to match).