AFD is not a vote. It looks like one, it has a lot in common with one, but it isn't a vote. It's an attempt to achieve a consensus decision, or failing that, to measure community feeling.
What counts most is the quality of an argument. Several registered users saying something does not outweigh one anon saying something else, if the lone anon's arguments are stronger.
The opinions of newcomers and outsiders count, but not always at full value - sometimes they just aren't representative of the wider wikipedian community.
The closing admin uses the page to make a decision, considering first the weight of argument, and then perhaps the weight of numbers. Mistakes happen, which is why WP:DRV exists. The raw numbers are a part of the process, sometimes they they are even the major part of it, but it's not a vote.