I think it's a broader reflection of how media is consumed today. Fast, short, high-dopamine hits.
Think about how stimulating cod is compared to 10 years ago. Constant action, addicting hitmakers, fast and constant slides.
Sliding is relatively easy, looks visually cool, and makes the player feel "faster" even if it's not. It's a short, quick dopamine hit. Endlessly repeatable.
For players that haven't experienced deep movement of a game like tf2, quake, etc sliding seems great. They're hooked on the fast feedback