.... Then you can downvote another set of spam in a row and likely lose less than 1 XP for each 3 you downvote.
I quite agree with your changes (++ by the way)) and view downvoting spam, rather than considering it, to be misguided. It may even be sufficiently misguided that it should cost the voter XP.
Nonetheless, the risk of losing XP for what the writer says he views as a community service (even if that notion is, in fact, misguided) may be a disincentive not only to that specific community service, but to any other which might be better-founded, unless we plainly state that "downvoting spam is deprecated. Consider it, instead."
Update (ca 21:35 GMT):
Gentle reader: my observations were colored by a misconception, corrected in tye
's Re^6: History now influences voting (reaps)
, below. It may be below the level of replies you usually read, but if anything I remarked above resonates, please see tye