Do most people in the UK think Americans are stupid or not trust them?

I keep hearing the term seppo thrown around which I think is Australian. I know the USA kinda sucks but do y’all really have a bad general view of us and if so why? Are British people told not to trust Americans?

Edit: I know what seppo means and wasn’t asking for a definition. Sorry if I didn’t make that clearer. My point was that I’m seeing it used a lot lately by non aussies including Brits.