Anti-Antis (Also referred to as Proshippers) are people who believe that they can ship incestuous/pedophilic/abusive relationships, because it's "just fiction".

These people commonly use the excuse that their ships are "just fiction" to glorify and push away the fact that their ships are commonly incestuous, pedophilic, and/or abusive.

They tend to ship adoptive/fostered family members together since "they're not blood related", or a minor with an alien/incredibly old/immortal being (such as someone of another species which lives longer than humans/has a different perception of age as humans, or some kind of god/divine entity/alien with no known or confirmed age).

The reason they're called Anti-Antis is due to the fact that they call people who disagree with their ship tastes "Antis", meaning that they are against or "anti" their ships.