I wouldn't say it's abuse, but it's certainly depriving the kids from learning how to develop socially. They aren't learning how to maintain friendships, and are being implicitly taught that such connections are disposable.

I've had the misfortune to see actual child abuse, from the story presented in the OP it doesn't rise even close to that level. Let's please reserve words/phrases like that for situations that warrant it.

It may not be an ideal parenting strategy, but claiming it's abuse cheapens the word. Are the children being fed properly? Are they being physically/sexually harmed? I've unfortunately had to intervene in a situation with my niece that involved the above 3.

The parenting method in the OP may not be ideal, but plenty of people have had childhoods like that My mom grew up moving every 5-8 months, her dad was a contractor for the TVA. There are still people who follow around contracting work. Please don't minimize that actual harm caused by child abuse by cheapening the term.