Any attack is wrong. I can't think of a scenario where violence as retaliation for failing to comply with a demand to kiss anyone else is justified. So, on the most basic level, we can all agree it was wrong (for a number of reasons).
Regarding the publicity, I think your second point is at least valid, regardless of whether it is right (I'm using those terms differently). At the core of your second alternative is the story's newsworthiness. Sure, attacks like this happen all the time, especially in bigger cities like London. Why are they not publicized? Two reasons: (1) because they would likely consume all of the media and (2) people become desensitized to the same stories over and over and over again. But, when something similar, yet different enough happens, the "different enough" aspect of it pushes it back into the spotlight of the mainstream media.
Another factor is certainly the mainstream media's leftist agenda in highlighting the mistreatment of marginalized groups to exacerbate their marginalization to further the media's leftist ends. I think this underlies the second alternative as much as, if not more than, the earlier points, which is what people find problematic. In short, it fits the media's agenda so the media makes it news. Wrong? I don't think a "right" or "wrong" answer is appropriate. The media is permitted to have it's own agenda, and we are allowed to support it or to disagree with it.
So, was it horrible? Yes. Does it fit the media's agenda? Yes. Is it receiving disproportionate coverage? Probably.