The frustrating bit is that this is absolutely not true. A compiler is anything that parses some text according to some grammar, manipulates it, and emits it in a different format. While the most well-known and popular compilers are for C, to emit machine code, there's nothing inherent in the definition of a compiler that means it can't emit something human-readable.
I wouldn't have nearly as much issue with this if the JavaScript community instead had decided "compiler isn't specific enough: we need different words for compilers that drop vs. maintain a level of abstraction", rather than "we need a word for a thing like a compiler, but that doesn't, as compilers apparently inherently do, drop a level of abstraction".
Then the JS world came along and decided to use a new word to make it look more hip and cool.
A friendly FYI... the old word "transpiler" has been around since at least the 1960s. See the 2nd-to-last paragraph on the last page:
http://comjnl.oxfordjournals.org/content/7/1/28.full.pdf+htm...
[0]edit: Apparently 60's.