The warn is valid whether you got to upload counter evidence or not. That's why your appeal got denied, the immaturity that you show is by not accepting this fact.
You bypassed the NLR system, although unintentionally it's still a rulebreak as Troller pointed out to you on your appeal.

Someone leading the sit or not doesn't matter as your evidence would only show that you bypassed the NLR counter. Bob warned you fair and square and if he wasn't controlling the sit then he just needs some more balls, but that comes with experience.