Chinese multinational, founded by a former People's Liberation Army engineer, has in the past also run afoul of US regulators and politicians on concerns it is closely connected to the Chinese military and Beijing.
There are a couple of things I think are worthwhile to realize about the US gov, especially when it comes to anything tech...
1st, like any gov I guess, whatever they tell you or leak is released to shape public opinion, &/or to help whatever politicians get reelected or otherwise stay in power.
2nd, very few real tech pros will work with the US gov proper -- they get fed up with the politics & glacial pace of change & quit. That's not to say there's not some sharp people working on the staffs of different candidates or Congressional Reps/Senators -- just rarely in the ranks of the gov itself.
3rd, most serve themselves first, the people & their government 2nd or 3rd... There's a Huge intelligence contractor industry in the US, whose main, underlying purpose is to keep their contracts & get more, bigger contracts. [type "us government intelligence contractors" in Google] The officials doling out those contracts often have their own agendas, priorities, &/or people that they want [need?] to please.
So... Has some group or agency in China hacked into whatever gov systems? More than likely, because it would be in their country's interest, just like I'd imagine several other countries who have very likely done the same thing -- China is relatively young when it comes to tech, so it makes sense to me that other intelligence agencies with more experience have been doing the same things longer, & perhaps better. [When it comes to intelligence agencies, the US itself is comparatively young.]
I'm not disagreeing with anything -- just saying don't put absolute faith in anything the US [or any other] government says publicly, & maybe ask: "Why"? In this case [Huawei] it may not make sense to you or I, but it has to make sense to someone(s) or else they would be banned. What's the benefit to or for Optus, Telstra and Vodafone? What's the benefit to the government, or the people in the government? Yes, governments do stupid things, but that's from our perspective rather than those in power -- they don't do anything that doesn't further some goal, be it their legacy, ideology, *retirement* plan, or whatever. :)
