I see your main problem - you don't see a difference between moving 5ft and a 5ft step. The first is just normal movement. The other is your entire movement for the round and is considered a defensive repositioning.
You are only allowed one 5ft step per round, correct?
So, if someone used their 5ft step for the round they couldn't be bullrushed 5ft, because they've already taken their 5ft step for the round?
It has been asked, and clarified, that moving 5ft is NOT a 5ft step. If you don't want to believe that fine, but that's just being stubborn. You weren't here when that discussion took place, and thus it is fair that you didn't know about it, but that's the benefit of having long time board memebers around. We remember stuff that happened before and can pass it on.
Anyway, there is no point in continuing to debate this with you because we have fundamentally different views - I see a 5ft step and 5ft of movement as different things, you do not. Thus, we will always disagree with this.
IceBear