“and I’m talking to apushatayid first comment”
The shayla with the shampoo that contained yogurt was presented to the Rosh Yeshiva at the time who ruled that it should not be used. Perhaps you heard of the Rosh Yeshiva, someone named Rav Moshe Feinstein Z’l. Feel free to rely on your own lomdus and knowledge of yoreh deah. We relied on his.
“Obviously, when you move to “flavored” waters, special energy drinks, etc, some hashgacha is definitely required”
And since the average consumer has zero knowledge of what is bottled where, and what goes on at the bottling plant, it is foolish to disparage the hechsher on a bottle of water. It may be true that in many situations no hechsher is required, but, sometimes, companies use a kashrus symbol as a marketing symbol more than anything else. they are already paying, say the OU, to supervise a plant and use their symbol on all kosher products, that they will use it on those products that dont need it.