And yet "panics" exist, with very similar semantics to exceptions in C++/Java/Python/Ruby.

Sure, there's differences between Go panics and any one of those implementations of exceptions (just as there are between them, or between any of them and Perl 6 exceptions.) But panics are clearly a variation on the exception theme, just as each of those forms of exceptions is.

The strong idiom of not having panics exposed across public interfaces of libraries is a cultural change, which to the extent that it is followed does present a simplification compared to ecosystems where you have to deal with both returns and exceptions in library code. But panics very much are exceptions, and changing the name doesn't change that.