What do we do about that?

Well since only SaidIt clones will have the same voting model, the best we can do is work around it. If a downvote comes in, it's discarded (edit: or subtract downvotes from the upvotes if both are present). For a fun vote to go out, it either counts as another upvote or it's discarded. Etc. etc.

Do you want to try to explain, or just leave it?

I'm just gonna live and let live. Maybe they like it because it ups the cringe factor. Surely they will notice the score in the sidebar not subtracting points on "downvotes" sooner or later. Edit: they have already changed them anyway.