I'll agree that exercise of any kind (except perhaps the dangerous and excessive) is better than none at all, but there does come a point where you are not challenging yourself at all and you are only going to the gym to waste time.

Since you're there anyway, you might as well get something out of it. Unless you are atrophied to the point of near death, curling 2kg isn't going to do much for you... that's like picking up a stapler at work.

I know the thought of working out sucks. You are effectively torturing yourself to make yourself stronger. It sucks to crawl home sweaty and tired, and to go to work sore the next morning. Such is the price for having people want to secks you.