The FBI isn't saying "normal people are at risk from FaceApp" but "US intelligence is at risk from the use of FaceApp". In the (very short) linked letter, it specifically calls out "elected officials, candidates, political campaigns, [and] political parties".
Considering all US intelligence agencies unanimously agree that Russia already attacked US candidates and political parties in the past, saying "yeah but everyone does it" is about as off-topic of a remark as you can get. To my knowledge the FBI has never publicly disclosed Australia's efforts to meddle in US elections.
Australians legally do metadata and spying better than everyone else on many metrics and then share it with the multiple eyes. Something to remember when the media is whipping up a threat frenzy.
Given Australia's treatment of whistleblowers and slow descent into authoritarianism, I very much envy the few protections Americans take for granted.
I've seen this sort of "argument" a lot lately. Not sure why people think it communicates anything other than lazy cynicism.
That everyone (to a rounding error) has sex does not mean that everyone has sex with everyone.