1. Triplebyte attempted a big move against LinkedIn, tried to ease the blow to users by dumping on a Friday before memorial day weekend
2. Triplebyte, the company built around helping people find jobs, truthfully didn't understand that people might have concerns about their current companies knowing they are job-hunting
It's pretty obvious it's #1, and that opt-out rather than opt-in was the only way it would gain the critical mass needed. The outcry hit critical mass and now they need to walk it back, until they have a different strategy for re-segmenting LinkedIn's market