It's because every single article that's promoting ECS does so by comparing it against incorrect inheritance-based code. The amount of time you see newbies jumping on the ECS bandwagon because inheritance is bad, while they don't yet understand OOP, ECS, procedural, relational, or functional... is infuriating.

Do both. Teach how to use composition. Teach how to use the relational model. Don't avoid teaching either by using misleading sales tactics.