Take this query from the suggester:
Now read [[mw:Manual:Category table]]:
"Track all existing categories. Something is a category if it has an entry somewhere in categorylinks, or it once did."
So it's logical that something like 1895 establisANONYMOUS IS LEGIONhments is in the suggestion list, but it is really not desirable. It contains many 'bad' words and deleted stuff that we don't really want to present to users.
This can be easily solved by adding:
acmin=1 to the query.