What's the deal with Juice?

We mainly give our 21 month old water. On rare occasion she might get apple or orange juice. But every morning she gets fresh squeezed Orange. At my in-laws they have a habit or watering down juices and tend to give her that despite telling them from the start water only. Now, my LO will want plain juice and they told me it's so high on sugar. No shit, really, as if I've been talking to a wall. Not to offer any juice even watered down. So now, I had to hear them talk about how bad it is. What the hell is wrong with some people? Do I just tell them once again mainly water and if they don't want her to have a plain juice not to offer at all?

**Just to be clear, I did write on Rare occasion, which means maybe once a week as opposed to going to my in-laws 4x times a week offering her juices

** Squeezed orange juice is not the same as bottled. My daughter doesn't take the watered down juices, if offered she wants it pure. So my in-laws said watered is better and only offer her juices when I'm not around and they wonder why she won't take it. I keep telling them only water. Especially when she gets sugar from them ontop. So pretty much I'm on the wrong because when I give my daughter juice it's pure.