All you need to understand it is contained in this one quote below, as reported by my colleagues Greg Miller, Karen DeYoung and Ellen Nakashima:
"Being seen as having the US government force our hands makes others around the world lose confidence in us," said an industry official, who spoke on condition of anonymity, citing the sensitivity of the discussions. "We understand that the White House [has] a political need to show progress, but we don't necessarily share that political need."
Tech companies appear not to like being bossed around by governments.
Whether it's Google pulling out of China over censorship concerns or Twitter suing Turkey in connection with its ban on airing "terrorist propaganda," or Yahoo fighting US surveillance requests, Silicon Valley has sought to avoid getting too close to governments.
The whole ethos of Silicon Valley depends on the disruption - or transcendence - of traditional power structures. And so when politicians make requests of tech companies, it's that much harder to convince the tech firms to say yes. Bowing to those requests hurts their credibility, and can lead to actual losses in revenue.
That's why simply "asking" for Silicon Valley's help in fighting ISIS is way more complex than it sounds.