It seems like there are thousands and thousands of counterexamples to this very dogmatic statement. Apparently there are some much more phonetic languages. Just the fact that English has absorbed words from so many sources would seem to limit the reliability of phonetic pronunciation rules.
Every language that uses the alphabet (or any variation thereof) is a phonetic language. The fact that nearly all phonetic languages have absorbed words from other languages doesn't negate that.
The fact that you can also somehow learn to read English through the whole word sight reading method also doesn't negate the fact that it's a phonetic language.