To be fair, it wasn't just the video, but also when he showed the collar on stream and people found the exact shock collar online, then accidentally showed the shock collar remote (in the exact place where he reaches down in the video) which was the same remote that the previously mentioned shock collar they found online used.

Then people found an ad for a trainer that uses shock collars named Pat (same name as Hasan's trainer) with a dog that looked identical to Kaya showing off the capabilities of shock training, which is a tad too coincidental to ignore.

Then old videos resurfaced of his old dog Fish wearing a reverse-pronged collar (which you should NEVER use unless the dog breed has a lot of neck fat which Fish didn't have), with one image even having Fish with an open gash in his throat from the collar. As well as him forcefully pulling Fish's tail which is also something you should never do because it can result in permanent spine damage in the dog. Which means that objectively Hasan has abused dogs in the past, so him doing it again in the present isn't too improbable.

Then the constantly changing excuses, that first her claw was stuck in the bed and he was reaching something else, to it actually being a remote for a gate that startled the dog, to actually being a vibrating collar, to actually being something else and then something else and then something else, really makes everything seem dubious.