Well, completely ignoring any effect the scene has on Han's character development, I think most people get outraged because it doesn't make sense that Jabba would send a bounty hunter that can't shoot someone sitting across the table from him. Because it makes so little sense on its own, the only purpose it serves is to change Han's character from the original. Frankly, I'm not sure that Han would have survived so long if he waited until getting shot at before shooting. So it's really the inanity of the change that I think people take issue with.

XP was released 10 years ago and people upgrade their computers much more frequently than they buy new cars.

If it was a model of car that was 30 years old and someone found a serious safety problem, the unanimous verdict would be to buy a new, modern car.