The idea that people react differently to images of people that look different is hardly cause for alarm. Its an innate biological reaction from our tribal days, which evolutionary wise, were last week.
In one specific instance, no it is not reason for alarm. That it is growing in the aggregate is a reason for concern. We need to quit pretending that racism or simply racial bias is a thing of the past or it will continue to creep back up on us.
This board is crawling with flag waving racists. Well, actually I am guessing there are only 3 of them and they just make themselves seem more numerous.