Because before people realized the extent to which the US government was co-opting industry to be part of the spy apparatus, people had no real understanding of the issue.Via Detroit Steve.
Since every US firm is covered under the Patriot Act which says "we can demand your data in secret", now that we know just how untrustworthy US firms are, buying from US firms is idiotic because it's patently obvious there can be no trust.
Snowden didn't cause this, per se, but if he hadn't made it so damned plain that the US government and US firms can't be trusted, then people would still be oblivious, and the NSA could spy in secret.
Honestly, I think US firms deserve to lose truckloads of money as they're no longer welcome to try for certain kinds of business.
Because hitting America in the pocketbook seems to be the only way to affect change.
But make no mistake, on a global scale, the US and all US industry are no longer trustworthy entities. And we no longer buy your narrative about the defenders of liberty, democracy, and freedom
... you're petty fascists who demand the world bends over for your security.
We don't give a damn about your security if it means giving up our rights. In fact, if it means giving up our rights, the world is increasingly saying "fuck your security".
So, boo hoo, people will stop buying your products. That's your problem.