It seems to me there's second-guessing, and then there's second-guessing.
I think it's perfectly legitimate to ask whether the Concorde taxied out and/or began its takeoff roll overweight, and why the crew didn't switch runway when the wind shifted. These were all decisions the crew took calmly and deliberately. There are procedures and regulations to follow. If there are doubts, there is both time and the means to resolve them.
Once in the air, on fire, too slow, claxons blaring, I find it a little less legitimate to argue about whether every split-second decision was right or not. Should the crew have tried to put down the airplane at once? Given that we know the outcome of not doing so, it's easy to say it would have been worth a try. But certainly there's enough uncertainty about the likely success of such a maneuver in a high-weight, high-speed jet loaded with fuel and already on fire. With Le Bourget so close, with a nice long runway, fire services, etc, that's a gamble that I can see myself making. It doesn't even require a 180 turn, just a fairly shallow turn, into the problem engines.
So I say, let's by all means examine very carefully the events and decisions that led that Concorde to have to take off on fire, including technical issues (fuel tank design, tyres, etc), procedural (ADP runway inspections), operational (weight calculations, runway selection), and serendipitous (that metal FOD, and the 747 in the Concorde's path). And if does turn out that the crew made mistakes, let's not shy from criticizing the crew for any errors or rule violations they might have made. Great human being or not, when you take up some 100+ people, you accept a lot of responsibility. But let's end this rather sterile debate about whether attempting to reach Le Bourget was preferable to putting the aircraft down in a field. Even from the comfort of my living room, with time for reflection, analysis of available crash statistics, examination of photographs of the terrain, and all the other luxuries Marty and his crew lacked, there's enough doubt in my mind about either course of action as to make a decision difficult. In the pilot's seat, with the stick shaking, alarms blaring, and my own life and those of 110 other people in my care at stake? I'm not going to second-guess anyone in that situation.
Somewhere in between these two cases is the engine shutdown decision. Yes, it was under pressure, but it also (apparently) went against both SOPs and common consensus. SOPs are there for a reason, and a particularly important reason when they deal with emergencies. So I think it is legitimate to ask why this shutdown took place, and especially whether its a systemic problem of poor CRM training or habitual disregard of SOPs.