No seriously does anyone know how to delete threads

But that did get me thinking about it so who knows?

I honestly dont know

Garlic already explained the majority of it, but another aspect to remember is that: In order to become a finalist, the community votes on a specific submission by giving it a diamond.
The fact that certain moderators then get enough "votes" (Diamonds) from the community, isn't something they control themselves. Heck, we can't even choose which submissions are accepted as finalists with the tools we have :'D All we can do is - Just like all members of PM - create something that gets enough diamonds to become finalist in the specific contest :D

Some of the moderators (especially DreamCritting) are very active in the community and participate in all the contests. It doesn't take much to place in the top 50 out of 150-250 entries when many of the entries are either off topic (don't fit well with the contest) or made by young artists without as much experience as an adult who has been doing this for years (as a moderator would have to be). In the end, moderators are not getting preferential treatment, some of the better skinners just happen to be moderators.