I don't like the Python approach either, but I would not call it dealbreaker.

I think dealbreakers for me are things such as complexity. C++ complexity is a dealbreak for me.

Perl lack of readability and structure is a dealbreak for me. Not any particular syntax choice.

Java is almost a dealbreaker to me. But not because of one specific syntax but rather due to the overall verbosity of the language, and the overly complex software practices. The deep nesting of namespaces. The complex inheritnance and composition patterns usually follwowed.

For Python I don't think it is whitespace but the complexity it has developed over the years. It started out as a pretty simple language. But now the Python ecosystem has ballooned and become kind of unmanagable IMHO.