I'd say separate them, and try not to use the same put-down multiple
times. After all, a put-down has to be appropriate (used for someone
well beyond listening to reason), and it should not be too annoying to
other readers. So avoiding repetition is good, as is being witty in
some way. It can be okay to cut-and-paste the same put-down multiple
times in one reply, where the post is just so hopelessly wrong that it
is too much effort to correct. But repeating the same rather dull
put-down in multiple posts is poor style, IMHO.