They don't let you upload facefusion videos. The video has to come from the front-facing camera on a phone.
There is an extremely profitable company (whose data hoard keeps geting hacked but why should they care?) built around this:
https://www.au10tix.com/
Most apps use device attestation (derived from secure boot) to make sure the video stream is really coming from a front-facing camera on a physical device. If Hinge isn't doing this yet they surely will be in 5, 4, 3, 2...I know, but you need to think like someone trying to get around the limitation with the lowest effort possible.
They don't feed it a video clip. They hold the camera in front of a screen playing the video. Use a low-end phone with a blurry camera to increase your chances.
Can someone not just have an additional device and play a video on top of it?
Fundamentally no amount of front facing camera on a physical device or other shenanigan a company might do can really do anything about it?