Well, fundamentally the NSA is the tip of the spear for a large industrial espionage ring to the benefit of principally US manufacturers but secondarily US allies. Every single country currently dumping Huawei has had beef with the US over its spying and wiretapping in the past.
But at the end of the day, every single country currently dumping Huawei has treaties and trade and favored nation status with the US. I'm willing to bet this is a "devil you know" situation - "yeah we've been caught with our hands in your cookie jar numerous times over the year, buddy, but you and I both know it's largely worked out for both of us more or less. We might read your mail but you know we have your back. Can you say the same thing about China?"
...and that's probably why nobody's saying shit.
"Violated the trade embargo with Iran" - I mean, Toshiba provided gear for Soviet submarines. It made congress really mad (wonder if I can find the photo of little old Republicans smashing a boombox on the capitol steps) but Toshiba didn't even get embargoed, let alone have executives arrested.