No, you can easily cause injuries from bad form that you wouldn't have gotten simply by doing nothing. I know several people know who broke or damaged something in their bodies and a few who needed surgery to fix it due to bad form over time.
I again claim: many more problems arise from doing nothing and getting really out of shape, rather than from doing one of the "wrong" things. You know several people that have been injured, i don’t doubt this. But in the US, 40% of adults are obese[1]. Europe is better but still bad (~20%).
Obesity is rather unrelated to exercise, it is about diet primarily; one can do nothing wrt exercise and still be thin. Injuries in terms of suffering are far worse than being unfit (not necessarily obese but not exercising in general), the amount of pain is incomparable.
