This is a great word! It is in no dictionaries, but it crops up in several academic papers because there is NO OTHER WORD that sums up its meaning! Right now you can only say "I reject the manufactured pejorative sense of this word!" You should be able to say "I reject the manufactured pejorativity (or, I suppose, pejorativeness) of this word!"
So start using this word, people. Because it's legit.