I really don't understand the supposed equivalence here.

WhatsApp's one and only feature is private direct messaging. Basically equivalent to iMessage, SMS, eMail, etc.

edit: Did you mean that this content is being spread maliciously by spammers using WhatsApp?

I didn't want to single out WhatsApp, but it's popular and I use it daily myself. Specifically I'm referring to their gif providers (which I believe are Giphy and Tenor.) and is essentially content available to everyone who uses the app.