As of 23w35a, the ravager no longer attacks entities through blocks even if they're thin like iron bars, however the roar can still hit entities through blocks. You could argue this might be intended because this attack affects all nearby entities within a range of the ravager, but firework rockets, which also deal damage in area, don't have this issue.

How to reproduce

1. Summon a ravager behind a wall of glass, apply slowness to the mob if needed.
2. Equip a shield and make the ravager attack you until it gets stunned.
3. When stunned, quickly hide behind the wall of glass.
4. Notice how the ravager roar hits you.

Expected result
The ravager roar wouldn't be able to hit entities through walls.

Observed result
The ravager roar can hit you through blocks, even though it can't while attacking normally.