I can see it go both ways.
If you check the list, it also mentions other mechanics such as locating enemies through things happening in the fog of war. Window crushing, fences getting destroy, sound, xp kickers etc. Depending on who you ask, ghosting can be fine.
Some people consider blocking retreat path with other infantry or vehicles abusing. Same with pushing.
No one bats an eye if you attack ground to luck yourself and get a scatter hit outside the range of the weapon or try to shoot through a sight blocker like a building.
If the enemy doesn't know to press stop, you can make vehicles phase through each other.
What's consider a skill, mechanic or knowledge to be ok is entirely dependant on what the community believes to be fine.
I'm talking based on experience in SC2, WC3, AoE, FPS and fighting games.
To some degree, sure. At least personally I'd call all the "Fog Mechanics" (Barring perhaps sounds?) to clearly be bugs. I suppose it's up for interpretation.