Slip and turn,
In short, yes, you are being unfairly critical.
You were a passenger and the PIC (well, probably both flight crew) made a decision that adhered to policies and law, therefore I think you are being a tad arrogant to assume that you would have 'made a better decision' by taxying the extra kilometre.
I don't tell everyone how to do their job. Do you?
In a Cessna 172 on a major airfield, do you taxy to the start of a 4km long runway, just in case? That would be ludicrous wouldn't it? Sure, not quite the same, but shows the logical progression of your thoughts. Intersection takeoffs are quite common because the aircraft simply does not need the extra bitumen in order to get airborne. V1/V2 are still within limits, so it's wasted runway...
Just my thoughts, let the professionals make that decision I say.
Matt