Oh FFS what is it with you Brexiteers ? Talk about touchy - you are so easily offended. It's embarrassing.
You have a statiscally average spread of qualities in a population. You remove some based on being above-average in an arbitrary quality. What is left is by definition of lower overall quality, or "dregs" by that measure. It's not a nice word, agreed. But then what Brexit and it's knuckle dragging supports have done to the UK isn't nice either and don't ever think you'll get an easy ride for it.
I guess this must be related to the times when someone says "I'm not a racist but .." before literally defining a racist behaviour.