Despite what we think as normal or not it is really up to you, the end user, the one whose experience is either good or bad.
Personally I wouldn't feel good with a touchpad moving from side to side, and no matter what excuse may a retailer might come up with for not replacing it, it is a obligation to my self-respect to let the company know that I am not feeling good with it.
Just because you are a consumer does not mean you are small. Trust your judgement more and do complain because this is what most companies rely on. That you might not go into trouble for such a little thing. However you paid every penny for it, haven't you?