Nah man.
I talk as if games 4 and 5 in the Edm series aren't as important (not games 3 & 4 as you incorrectly summarized). Because Florida was already up 3-0 going into game four so the outcome of the series was already basically decided. When Edm got close in the series (ie 3-2), McD's offense dried up. The argument is a basic argument.
Re: gm 3 (in the Edm series), I don't think scoring two points in the third period (when the team was already down 4-1 going into the third) is all that relevant. This is also a basic argument.
Re: Pittsburgh series in 2009, I absolutely think games 3-4 were important. Because the outcome of the series was in doubt at the time of Crosby's offensive contribution, despite Pittsburgh being down 2-0 in the series. In hindsight, this argument ended up especially valid because Pittsburgh did end up winning the series despite losing the first two games. This too is a basic argument.
So, a few basic arguments here one after another.
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I think you are one of very few that would describe these arguments are "FAR from basic." Actually this particular argument is very basic, almost embarrassingly so. It should not have to be repeated multiple times over multiple posts but that is what you have asked for.
Imo the fact you've asked for clarification / insisted that this is not a basic argument says more about your ability to understand an argument than anything else. This particular argument truly is basic and not intended to be difficult to follow or understand.