You got the "primary stat" right. However, endurance is the number 1 stat for any and all classes really (not just for tanks, as you say).
I didn't say that it was just for tanks. I stated that it may be in your better interest if you frequently play the role of a tank. I also said, "Even if you're not a tank and if survivability is quite important to you, then raising Endurance more may be a good idea for you," which you even quoted.
I play IA Operative. Cunning will make me do more damage, and it will make me heal more. But I can't do any damage if I'm dead, and I can't heal anything if I'm dead. So since endurance makes me not die, Endurance is the number 1 stat. Cunning is 2nd only.
Whether the primary stat (i.e. Aim) or the secondary stat (Endurance) is the "number one" stat is really up to the player. It depends upon what is more important to the player. If a player wants to dish out higher damage or greater healing, then raising the primary stat may be the better choice. If a player would rather have better survivability, then raising Endurance may be better.
In your case, you would rather not die, so Endurance is the "number one" stat to you. I'll let the individual player decide on their own what they consider is the "number one" stat to them.
For most people, the primary stat should be fairly obvious, since most of your quest gear is aimed towards this stat and also the PvP armor that is class specific etc. But nice of you to write a guide for those that didn't notice the hint.
I'm sure it seems obvious to many people, but I have also seen many people in beta and in retail ask about this as it seems unclear to them. This is why I wanted to pitch in and write this guide.