(That is, the person who wrote Slate’s Facebook feed did a nice job of pointedly using the Britishism rubbish in reference to the British Piers Morgan [whose chat show was just cancelled by CNN.])
Saying something “was rubbish” (or just saying, “What rubbish!”) isn’t nearly as British to me as the adjective use: “Some people adore rubbish science” and the like. (No, I haven’t checked the facts — has Lynneguist, I wonder?)
I think rubbish-as-noun is pretty British (and New England-ish), and rubbish-as-adjective is very British. Got into this issue in several posts on “crap” (most recently https://britishisms.wordpress.com/2013/02/10/crapper-vs-crappier/) and “shite,” which is used in the same adj. way.
notoneoffbritishisms.com 
Is that canceled or cancelled?
LOL! Hasn’t there been a long thread about rubbish already?
Saying something “was rubbish” (or just saying, “What rubbish!”) isn’t nearly as British to me as the adjective use: “Some people adore rubbish science” and the like. (No, I haven’t checked the facts — has Lynneguist, I wonder?)
I think rubbish-as-noun is pretty British (and New England-ish), and rubbish-as-adjective is very British. Got into this issue in several posts on “crap” (most recently https://britishisms.wordpress.com/2013/02/10/crapper-vs-crappier/) and “shite,” which is used in the same adj. way.
Of course Language Log has it: http://languagelog.ldc.upenn.edu/nll/?p=4295. Many comments on regional use both literal and figurative.
You can also say ‘I really rubbished his argument’.
I think the way Americans differentiate between garbage and trash is quite good. We just say it’s all rubbish.
Perhaps they’re better at recycling!