Why cops suspect a certain community why security people suspect some community first.
Thats because of the general behavior of certain people of that community.
If you show more violent tendencies, if world over people commit violence in name of your faith, if you have more number of people who dont seem to be doing constructive work but rather cause problems then cops will suspect you.
When there is a theft in an area chances are that the security will round up those people who have displayed such behavior in the past.
That does not mean they are biased, they are just following a logical path.
Because of our past behavior people tend to typecast us everytime, does not mean they have a grudge against us.