Why anyone would rip on you for this is beyond me. A 64mi hilly ride I am going to do in a couple weeks has 0 gas stations, parks, etc along the route so I need to either bring what I will drink or stash water on the route ahead of time.
My gravel bike has 3 mounts and I with probably also use a large under saddle bag to hold a couple 16.9oz waters as well as food. Thatll be close to 100oz of water and will be great to have if its on the warmer side of things.