A very high proportion of loan words, along with significant differences in grammar, phonetics and orthography. That's why people think of it as more of creole (or hybrid) language.

None of these are reasons one should consider it a creole language. It may have been influenced by other languages, but that doesn't make it a creole.

You can go find a linguist to debate this if you want. My basic points are simply: (1) the author of the original article wasn't making much of a point, and (2) in regard to what you were saying, where exactly English sits on the spectrum of hybrid languages is a multi-faceted issue -- rather more complex issue than simply the proportion of loan words.