On the whole, I think I'd rather be spied on by an ally rather than a dictatorship.
Our biggest trading partner is China, and we have a free-trade agreement with the US.
Who exactly is our ally again?
Stalin was a mad man on a par with Hitler, but even under later leaders it was still a repressive regime with Gulags.
When you say that you doubt it, is that code for having no idea of the impact of Soviet funding in South America, but not being willing to say that you don't know? Or is it just that you know that everything bad that the US did was to counter something even worse that the evil USSR was doing?
Missile gap?
However, Cuba is a repressive dictatorship which will was funded by the USSR for many years.
Sent aircraft carriers, ships and soldiers to help depose a democratically elected president, just because he wanted closer ties with China and wanted to do agrarian reform.
Disappeared lots of people (I don't know any personally, because I am too young, but I DO know personally lots of people that still want disappeared people back)
Spied on us (erm, that part still applies, no?).
Sabotaged our agriculture (ie: some plagues started after US agrarian engineers visited us to "help" with our agricultural technology).
Supported and funded very repressive crazy dictators that killed boatloads of people.
What the USSR did for us during the cold war: Gave us some really cool technical books in spanish (yes, our language is portuguese, but spanish is good enough), I still have a bunch of them, they are really good, somewhere around my house there is calculus books, structural engineering, and lots of other cool stuff, russian books but written in spanish, targeted at Latin America.
USSR borrowed us some scientists (Russia and Ucraine still do, by the way).
Helped our exiles, not only left wing ones, but right wing ones too.
Sold us some very interesting stuff, even if shitty sometimes (example: during the cold war Lada cars were very popular here).
Computers! (for example when some companies here tried to develop a computer compatible with the Macintosh, US government helped Apple in forcing them to stop, while Russians borrowed us some engineers and books)
Now, who were our real enemies in cold war again?
Stopped us getting nuked or invaded by the USSR
The fact is reality is much more complex than your simple statement which is further skewed by Hollywood.
It is just that this is what happened to us in Brazil, and USA never gave any clear indication that it wants to improve its behaviour.
So, why should we trust it now, if we could never trust it in first place?
It hurts a lot more because you are meant to look out for each other, not distrust and stab each others back.
But who is to speak for tomorrow? None of us can tell what the future brings. Not me and not you. So who is to say that in ten years, when that data is still there, that the US is still worthy of your trust?
It is the future we should distrust, even if you trust the past, and the present.