No, imagine it this way:
Your digestive secretions are intense, and transit time fast. No matter how intense your secretions are, some of the food will be left undigested. That will then foster SOME bacteria growth, even if you poop it out quickly.
Now imagine your digestive secretions are just as intense, but your transit time slow. In this case, since the food sits long enough in the small intestine/stomach, it will be completely digested. It will spend a much longer time in the colon, but because there's hardly anything left, you'll get no bacterial growth.
Now, if your digestion is very weak, then it's better to have a fast transit time, since there will be lots of leftover nutrients--better to get them out quickly before they cause harm. But that's planning for failure. If your digestion is weak, the proper thing to do would be try to improve digestion strength via physical activity, coffee, and other things that improve hunger.
Physical activity whether walking or lifting weights, increases stomach acid output? Or is it just due to general health improvement from exercise that digestion also improves