Today you provide sigint to Ukrainians, tomorrow you cover up for KSA killing another dissident https://theintercept.com/2014/07/25/nsas-new-partner-spying-... or assist in waterboardings https://theintercept.com/2016/05/16/nsa-closely-involved-in-...

(Never worked for intelligence agencies)

I think working for intelligence agencies, especially taking technical work (think sigint, encryption/descryption, malware/malware defense, etc.) is very, very interesting, but improving humanity is a huge burden that no agency can shoulder.

On the other side, I think someone mentioned that the work of the intelligence agencies is not to prevent wars, but to prevent world wars (not exactly what he said but I believe it is what he meant). From that perspective, they are "helping" humanity.

Do you feel US government helps improve humanity or reduce threats to humanity?

There’s your answer.

Non-US intelligence agencies exist.

They all serve their regimes. Some are better than others, but ultimately you would have to put your trust in a few old white men to make wise decisions.

Obligatory:

https://www.youtube.com/watch?v=mJHvSp9AKYg

I love that scene. But it is worth noting that besides the signals intelligence (SIGINT) mission and Tailored Access Operations the NSA also has a mandate to secure US communications.

In other words, not just code breaking, but code making (and other facets of security).

Of course, the NSA has also been caught a few times deliberately weakening the security of US communications in order to give themselves an edge in decryption when COTS products are used by adversaries (betting that no one else would be able to make use of the same weaknesses), but there are other agencies that aren't quite as… conflicted (eg. CISA).