Why do some non-asian people say "ni hao" to Asians although they dont know their real nationality?

I have traveled some cities in the US and some countries in Europe so far. Then, some people who just passed through me said "ni hao" to me. I am a Ja

I have traveled some cities in the US and some countries in Europe so far. Then, some people who just passed through me said "ni hao" to me.
I am a Japanese girl and I know that it is difficult to distinguish Chinese, Korean and Japanese. It's okay if they don't understand which country I'm from, but I don't really understand why they say "ni hao" estimating I am Chinese and give me this kind of unnecesary greetings. (I'm sure that if I look like the local people, they would not say "hello" or whatever to me.) They were not trying to draw my attention to sell something, but they were ordinary people who were just walking on the streets.
Why are they saying "ni hao" when they see asian people? What are they thinking when they say it?
To be honest, I feel annoyed when strangers say "ni hao" to me. Thus I wanna know what makes them to say such a thing to understand them.
I'm so sorry for my terrible English grammer!

or:I have traveled some cities in the US and some countries in Europe so far. Then, some people who just passed through me said \"ni hao\" to me. I am a Japanese girl and I know that it is difficult to distinguish Chinese, Korean and Japanese. It's okay if they don't understand which country I'm from, but I don't really understand why they say \"ni hao\" estimating I am Chinese and give me this kind of unnecesary greetings. (I'm sure that if I look like the local people, they would not say \"hello\" or whatever to me.) They were not trying to draw my attention to sell something, but they were ordinary people who were just walking on the streets.Why are they saying \"ni hao\" when they see asian people? What are they thinking when they say it? To be honest, I feel annoyed when strangers say \"ni hao\" to me. Thus I wanna know what makes them to say such a thing to understand them.I'm so sorry for my terrible English grammer!

or:They probably think that you are chinese, so they respond in chinese. They are just trying to be kind

Tags:fars,passed,countries,nationality,