I have to agree with this as a Brazilian. More over you can see the differences between countries very easily, it becomes even more apparent when you look to non-western non-eurocentric countries. Each country in Asia has its own way of meeting new people.
BUT there always exceptions (a lot of exceptions actually), and you shouldn't change your country based only on that. It is easy to find exceptions, shy people on Brazil, extroverts on Portugal, people who want something serious, or just date you a few times. The world is very diverse and there is a LOT of people that you can talk too. I can't say that these cultural differences make that big of a difference to be honest
BUT there always exceptions (a lot of exceptions actually), and you shouldn't change your country based only on that. It is easy to find exceptions, shy people on Brazil, extroverts on Portugal, people who want something serious, or just date you a few times. The world is very diverse and there is a LOT of people that you can talk too. I can't say that these cultural differences make that big of a difference to be honest