It is an abbreviation, and it means nothing in terms of beliefs.
Here on FR, occasionally creationists and evolutionists will start debating on a thread.
This is happening with increasing frequency.
Many of the same posters are involved in what has become almost a day-to-day passtime.
Some of these folks are creationists (or IDers).
Others are evolutionists.
As a shorthand, to refer to these frequent threads, somebody combined the names into a single word. As I explained in a previous post, the initial letters of the words CReationist and EVOlutionist were combined into a new word, CREVO to refer to these threads.
The meaning is: a thread where creationists and evolutionists are exchanging posts (and usually disagreeing with one another). It has no connotations.
I don't understand why you are casting about for a deeper meaning for this. As far as I know, there is none.
At this point, I think we have beaten this drum until it has no sound, but I appreciate your participation in beating the heck out of the instrument, to a beaten and useless pulp. Hopefully, none in the future will refer to a poster as a "crevo" in derogatory terms, thanks to just the two of us. Ain't that grand?