You are making exactly the same mistake I talked about. You are confusing "maximizing the chance of postponing losing" with "maximizing the chance of winning". Those are not the same thing.
You're right -- if you go for the TD there and don't make it, it's game over. But that does NOT mean that kicking the FG gives you the best chance of winning the game.
Here's an simple example to make it clear. And of course the numbers aren't as extreme in real life. Let's say at the moment in time they had to decide between going for the TD or kicking the FG they had a 50% chance of making the TD, a 100% chance of making the FG and they figured that given how crap the offense was playing that when they had their next possession they had a 20% chance of scoring a TD and a 60% chance of scoring a FG.
If they go for the FG:
100% of the time they get it, then 20% of the time after that they get the subsequent TD = 20% chance of forcing the game to OT (and so they lose 80% of the time)
If they go for the TD:
50% of the time they don't get it, and thus lose.
50% of the time they get it, then 60% of the time after that they get a FG which means that 30% of the time they force OT. And 20% of the time after that they get a TD which means 10% of the time they outright win.
Summing up:
* If they kick the FG they never lose the game at that moment, but they only force OT 20% of the time.
* If they go for the TD they lose the game at that moment 50% of the time, but they force OT 30% of the time and win outright 10% of the time.
Again, maximizing your chance to postpone losing (which is what kicking the FG does) is not the same as maximizing your chance to win, which this example clearly illustrates.
Now obviously how things work out depend on the exact numbers you figure applies to your situation. But it does show that a blanket statement of "you have to go for the FG there" is clearly wrong.
