Wikipedia is not a reliable source.
Nobody has argued that EMS is leading the category of suicide by profession.
US EMS/First responder suicide rates are likely underreported. There's no really accurate representation of suicide by EMS/first responders in the US. To argue numbers without numbers to argue is futile. That being said, we use the numbers we have to point to the idea that 400 deaths in the US, 34 in Canada and countless others around the world, all of which are preventable, and all of which were dedicated people working to help others, is too many.
Mental health issues are still stigmatized and negatively viewed by many despite recent efforts to make it known that this is a health issue and not something by which anyone should be shamed. Four hundred thirty four people may be dead. That may not be a lot in the grand scheme of things. But those 434 touched thousands of lives and that impact has to be worth something more than a casual dismissal.
MTA: Two last thoughts as this discussion is making me think.
1) If 434 deaths between the US and Canada aren't worthy of affecting some change what does the number have to be? 4340? 43400?
2) I disagree with the idea that EMS would have the lowest number because we see how precious life is. We see some of the worst that civilian humanity can offer. Military medical folks see the worst that an armed and militant humanity can offer. We may see how previous life is. But seeing that on a daily, regular basis gets old and affects people in different ways. It wears you down and grinds you to a pulp. That's what some develop PTSD. That why some wind up with life altering depression. Ultimately, that's why some choose to kill themselves.