A lot of good points have been made in response to the OP's question. An important point is that any host (the swallower) can be overwhelmed by a large enough population of foreign (to-him/her) bacteria (benign or disease causing) in food or water. If someone has a weakened immune system or simply hasn't traveled much outside their everyday environment, even non-pathogenic organisms in another state or another country can upset the GI system. Anyone who has had relatives from other countries visit in the US or Canada knows that GI upsets are not confined to visitors of Mexico.
When traveling, I don't know the condition of the pipes and the purification system, so I brush my teeth with bottled water and keep my mouth closed in the shower. Here at home, I know the condition of our in-house water supply system and we all have vigorous immune systems, so I have no qualms whatsoever and wash my fruits and vegetables without sanitizers. But, someone with a challenged immune system might well be wiser to use the water sanitizer.