Hahaha..
For one.. I don't think it's a matter of originality or not. There were a few things that could be linked to Salad Fingers, yes, but that doesn't mean that it belongs to David Firth. What you see here, and in many other flashes, is a certain style that I'm quite fond of. Maybe this author was influnced by David Firth's work, or the work of another animator that also may use a variation of this style. All in all, this is Kerpap's own style. You just can't duplicate what David Firth or other animators have, but you can improve upon your own style, which is what this person is doing.
Now, I ask that you stop saying how un-original it is and get to thinking about the important aspects of this flash: this person has -talent-. Talent that a lot of you, I know, cannot duplicate or possibly even hope for.
I hope to be seeing more work by you in the future, and don't let these comments make you dislike animating at all. Keep up the good work! ^_^