>>941554880 (OP)
Experience.
Same as with Russians in particular and Eastern europeans in general in Europe, and Brazilians in NA once they started flooding online games.
Then it started spilling over into real life, first because of spam and scam call centers,then more so in areas like the UK and Canada where their population grew quickly and they went from the owner of the local corner store to shitting up universities and lower income tech support jobs.
>>941554947
I will admit it was less of a hate and more pointing and laughing at how retarded they are, but there was still some clear dislike of them wherever they became common on the internet.