I would agree that Antibiotics play a part in causing Candida to overgrow in the body. If you actually look at some Antibiotics , they will list yeast/fungal infections as a possible side effect.
But I also believe that having a weakened immune system plays a part too.
It's probably a combination of the two. I mean, you are right that a lot of people take Antibiotics and never complain about yeast infections, so perhaps they have an immune system that can deal with Candida better than the unfortunate ones whose immune system isn't as strong. Or perhaps more people do suffer from Candida overgrowth after Antibiotic usage but they go undiagnosed...Who knows.
But yeah, it's good to take natural anti-fungals such as coconut oil, probiotics, cinnamon, grape seed extract, green tea, etc either during or after a round of antibiotics, just to give your body an extra fighting hand.