This is the accepted theory, but akshually there is no way from a linguistic standpoint that the "k" between the "s" and "l" would simply appear out of nowhere. The linguistics is impossible.
The etymology deriving from σκυλεύω makes more sense.
dispossed ennemy, captured, this makes a lot more sense indeed https://lsj.gr/wiki/%CF%83%CE%BA%CF%85%CE%BB%CE%B5%CF%8D%CF%...
than the notion "slav" would have somehow evolved "up" linguistically to get a "k" inserted. y'all know languages mellows over time, donty'all?
The etymology deriving from σκυλεύω makes more sense.