One important factor is how fast that 6 upvotes happened and from who. If it got posted and got 6 upvotes within a few minutes and that from "proper" accounts it is on the front page. If it has the same amount but it takes 30 min then not. At least from my personal experience.
This was at 19 minutes
The goal is to confuse us, so we can't fool the algo :)
In this case I assume the domain holds some weight?
Can't find the exact guideline - but mods give 'second chance' to some interesting topics on case-by-case basis.