The majority of suicides among men involve hanging, carbon monoxide poisoning and firearms. However, the majority of suicides among women involve drug overdose.
While it's easy to single out the means used as the differentiating factor as to why more men succeed than women at offing themselves, even though women attempt suicide 2 to 3 times as often as men, studies suggest it's not that men use more lethal means. It's been shown that men are likely more committed to ending their lives while women are using suicide attempts as a means of getting attention or help dealing with their problems.
To that point, when focusing on a single method of dying such as hanging (the number one method in the UK), men still succeed at a much higher rate than women.
I think it's been theorized that men don't think about the aftermath for others when they shoot themselves. The scene is a messy, violent scenario that someone must happen upon (creating trauma for that person/s), and someone must clean up the gore it creates. Women are more likely to choose a mice, neat method that doesn't create as much gore, like OD, hanging or slicing their wrists in a tub to contain their blood.
The bottom line is, suicide is a major concern in all countries, even those with restricted access to firearms. There is no data to support the theory that fewer firearms in society means fewer successful suicides. There are far more significant factors involved such as gender, existence of emotional support networks, etc
One would think a medical professional would know better than to use emotions rather than actual data to form his opinions.