Because other countries use different definitions for those things. The definition of a "firearm death" is consistent, someone was shot they're now deceased.
The definition of "gun violence" could be a gun that wasn't even loaded or fired in some countries (e.g. pointing it menacingly), bullet-injury in others, pistol-whipping in yet others, for one example.
Crime statistics are a complex topic, with politics, collection methods, and definitions playing a major part. For one example, richer countries often have higher "crime" because they're better at collecting and recording crime statistics, not because crime doesn't occur in poorer countries. Even richer countries like the US have a "crime gap" if you compare recorded crime with victim crime surveys (e.g. NCVS).
There's also politicization of reporting, at least in the U.S. I recall some states (Maryland?) have laws that mandate reporting of any injury related to a gun (could be a minor burn or a cut finger web that needed stitches) as a firearm-related injury. The intent, of course, being that people wrongly infer that these were injuries inflicted by bullets traveling at high rates of speed.
Dead's dead, though. We don't lose track many of bodies in the developed world.
Generally, you do find this:
. Include suicide in stats...is against guns
. Block suicide from stats...is for guns
I don't only fear for my life; I fear for my limb and safety and all the other good stuff too :)
(mind you, FWIW, and hopefully lateral to above questions, I'm not necessarily in the full "prohibit guns" camp, more of a "regulate&license", with thinking that since we regulate cars and airplanes and other potentially dangerous stuff that's even not explicitly made to harm we should regulate & license guns. But again, my questions above are from a more abstract perspective)