Because ven's reaction gif is an actual reaction, and yours is a girl looking back and forth at a camera with no visible emotion or reaction, or even non-reaction.
You pretty much said yourself 'oh he posted a Korean girl? i will too,' not realizing that the gif in his post had the context of being a person who is skeptical/deep in thought, while yours has no context other than 'Korean girl gif chain!'
It's fine. A warning is not a big deal. I'm not discussing this with you any further
A 'non-reaction', as you call it, is a reaction in and of itself. It signifies his nonchalant attitude towards the video, how it is insignificant to him, thus perhaps boring--yet not aggressively so. Subtle.
The response which some haughty authorities take, is 'this person is posting a reaction gif
because another person posted one. He's doing it for the intentions I do not wish him to have, therefore the action itself must be wrong'. This is of questionable logic, for if someone's intentions be dubious, yet their actions and effects acceptable, they deserve no hand-slapping.
I have confidence you have the intelligence to see, though, so why you chose to ignore it, or why you choose to make an arbitrary distinction between 'this reaction is acceptable' and 'this one is not', must be put to scrutiny. He took the passing of the other gif as a warrant to post his own reaction, and anyone with a thought to consistency in moderation must admit it as acceptable if they indeed see the 'non-reaction' that is a reaction.
You are in the wrong, and
your nonchalance about him receiving the warning is the greater offense to the decency we ought to afford our fellow mankind. The only acceptable outcome from this impasse is that you remove his warning and apologize, though it need not be public, and you will be a better person for it. And, on a broader scale, if you are not satisfied with my reaction because you believe it out of due proportion with the punishment he was given, this isn't about the warning he received, but for your benefit of becoming a better authority and person, and for mutual understanding to be reached.
Edit: More on topic, I'm glad this video was put here--probably wouldn't have seen it otherwise!
Tafo is very good at informing as to why we are as we are.
And, we should be as Tafo says we are. We need to be wary at all times of those who might take advantage of our brotherhood.