You probably know this.
But, there are a million different ways to bend a note. What pretty much remains true is that little of the bend has to do with your finger bending the note. A bend involves your finger (a little) and your wrist a bit and even your arm/forearm.
Eric Clapton uses just about his full forearm and his elbow as the pivot point to bend and shake a note. Others use more wrist.
This is important because, what the larger bunch of body parts does is what was said above, keeps your finger on the same spot of the string.
When you watch someone here or on Youtube, watch their wrist and arm too.
If you just push up the note with your finger muscle, your losing the strength of your grip on the string itself. using the bigger muscle groups instead of your finger allows your contact/grip in the string at the point of contact much more strongly.
This is my take, anyway.
