“but I believe the wider team all knew…. De la Rosa worked in the test team and was aware. I find it impossible to believe Hamilton and the senior leadership didn’t know about it. ”
Teams did know enormous amounts about other teams, from timing data, from analysing every square inch of photographs, and even from using sound recordings to measure the timings of competitors engines and shifts in their gear boxes. They probably even had people dedicated to analysing radio traffic of other teams and going through interviews etc, looking for any scraps of info for the jigsaw. You would also expect that when you recruit a designer or engineer from another team, they will be bringing a great deal of knowledge in their heads, and that’s what makes them valuable.
The difference with Spygate was that Stepney brought the complete tech specs, far more detailed info than he could possibly have carried in his head, and clearly that would be a legal issue for Stepney, so I doubt he wanted it widely known that he’d done this. For that reason, I am unconvinced that the source of the data was widely known at McLaren. It seems more reasonable to think that many people were seeing only small portions of this data were acting in good faith. I also think it likely that McLaren were not the first team to ever use some illegally obtained data, just the first where the scale of the theft came to light and to publically admit it.
In Hamilton’s case, it was early in his first year in F1, and he would have had very little experience of knowing how much data to expect in an F1 team, no benchmark for judging what was obtained legally by their own surveillance teams, and what was obtained illegally through the actions of a disgruntled employee. According to Max Mosely, it was Ron Dennis who called him and alerted the FIA to the situation, immediately he became aware of it from Alonso.
Whilst we’ll probably never know the exact truth one way or the other, I think we should be charitable, and not accuse people of being part of the conspiracy when there is no evidence to support it, and plausible alternative explanations.