Yes, it is. Anything with a wide userbase that worsens or even just intensifies mood will lead to elevated suicide rates. If your boss picks someone else for the promotion and you kill yourself over it, your boss didn't kill you. If you're attracted to someone and they marry someone else and you respond similarly, same answer. If your instagram friends post pictures of their happy lives and it makes you feel bad, etc.

You can broaden the definition of 'killing people' to include 'elevating their risk of killing themselves', but then you have to shed the intuitions that are the sole purpose of using that kind of language in the first place. It's a rhetorical sleight of hand.