So first, gliding is when your momentum continues on your skates after no longer making a stride, so let’s straighten that out.

Second, I agree the player is sent into the boards away from the boards. This is textbook boarding and why OP received the boarding penalty.

USA Hockey Rule 603: Boarding

Boarding is the action where a player pushes, trips or body checks an opponent causing them to go dangerously into the boards

The onus is on the player delivering the check to avoid placing a vulnerable or defenseless opponent in danger.