Просто - fits perfectly
Did you want to say "ему"?
Anyway "Америка не очень нравится" will be incorrect judgment
In 1925 he traveled to America and spent some time there. He was in several places in US and also he traveled to Havana and Mexico. He was reciting his poetry there. And as you may guess there were people who liked it. There were communists in US that time and quite a lot (even around 2000 members now, according to wiki) - Communist Party USA - Wikipedia, the free encyclopedia. As you may know the idea of communism was widely spread around the world that time
This verse comes from his verse collection - "Verses about the America" Цикл "Стихи об Америке" (1925 год)
And it's been written to show the "disgusting side" (or whatever you may want to call it) of capitalism/non-communism and religion