Based on my reading, the dust threshold went away with HF26. Here's a quote from The Evolution of Hive: Hardfork 26 by @hiveio. It's stated better somewhere else, but I can't find that post!

Dust votes, predominant among new accounts without much stake, are now considered the same as regular votes. What does this mean? Right now, if you were to delete a comment it would need to have no votes on it. Otherwise it won't be deletable, only editable. With this change, comments that have a dust vote (and are deletable now) will no longer be such. In short, all votes count.