I think we can all agree if any polearm has a spearstance that 1 shots every mount with it's rider and is super easy to land that mounts wouldn't be overpowered, but rather underpowered. Therefore any reasonable person should be able to agree the factors you listed don't make mounted builds OP if the proper counters exist.
I only claim to have a clue about things I have a clue about. This statement is pure simple logic. If the counters to any build are strong enough it can't be OP in a PvP context. Not claiming I know whose right, just saying your arguments against his position don't make you right unless the counters were too weak. And then the solution wouldn't necessarily be a nerf to the build as much as a buff to the counters.
You want me to conclude someone is a troll based on an argument I can poke holes in without detailed game knowledge. When you've called me a troll a few times yourself. Seems like anyone you disagree with is a troll to you.