... assuming [dangerise] is a word, that is.
Lexicographer
Erin McKean points out here that analysis of large corpora shows that “52 percent of the English lexicon—the majority of the words used in English books—consists of lexical ‘dark matter’ undocumented in standard references.” English is a productive language: speakers and writers can easily coin new words, by generalising from well-known morphological roots, by importing words from other languages, or just by making them up. Most words fall into desuetude, but some survive and prosper.
So it makes no sense to ask, as Matt does in the quote above, whether a lexical item is really a word. It makes sense to ask where (if anywhere) it's in use; it makes sense to ask in which reference works (if any) it can be found; and it makes sense to think about whether it's clear or useful or poetic or concise. But to ask if it's a word? Well, yes, it is. What made you think it might not be?
In this case,
dangerize, meaning "to emphasize or exaggerate the danger of something", seems pretty useful to me given the current tendency of politicians and security professionals to engage in the practice: a
Google Books search finds hundreds of hits.
