I'm gonna go ahead and assume that you mean downvote on the Musing platform here! XD And for some reason why do I get the feeling that this has something to do with my answer on this post: Would a flag option be useful on musing.io to help discourage spam questions and answers? XD
While there is no downvote button on Musing, one could still easily downvote a spammy question by just a simple copy and paste.
As an example, if I want to downvote this question I'm just gonna go ahead and copy the url of this page which is https://musing.io/q/broken.akay/f38m7yt45?r=answer
then replace "https://musing.io/q/" with "https://steemit.com/musing-threads/@" pointing me to the complete url on Steemit.com which is https://firstname.lastname@example.org/f38m7yt45?r=answer
And from there can easily be downvoted/flagged.
So yeah it is possible to still downvote a question/answer here but at the moment it requires some effort. XD