From this article it looks like Zuckerberg tried to strong-arm Snapchat first.
2ndly, it's business and not personal & I'm sure nobody understands its more than the shrewd businessman Zuckerberg.
Facebook CEO Mark Zuckerberg first flew out to meet Spiegel in his hometown at the end of 2012, according to Forbes, and proceeded to try scaring Snapchat's founders by telling them that Facebook planned to release a nearly identical app a few days later. "It was basically like, 'We're going to crush you,'" Spiegel told Forbes about meeting. That app was Facebook Poke, which proved to be a flop.
Zuckerberg paid another visit to the young company the following fall to make his bid to buy it, but by that point Snapchat's founders felt they had an edge.