It's not really a debate over a single water bottle. I'll be taking more banned items than a water bottle in... not arsed about that.
The issue is noted above. Madrid ran out of water. Before that it was a scrum before HT to get water/soft drinks (28 degree heat). No water fountains.
I think it was Rhi above who nailed it. It's disregard for fans safety and wellbeing. There should be free water. I think it was 5 euros in Madrid when available. Madness.
Not in any way acceptable and you are absolutely correct about it being a safety issue.
That said, Spain is very weird about water. There is never water put out for meals, and asking a waiter for a glass or jug of tap water is likely to be met with a blank or perplexed expression. On the occasions they do bring out a jug, they will only supply one glass for the person who ordered rather then for the whole table- so you have to specify how many glasses you want as well. The standard in night clubs here is to charge 5€ for a bottle of water and refuse to provide tap water - presumably to make up for the lack of drinks being bought due to everyone being barnetted. Walking the street here and looking at people out and about, you would think they just don´t drink water. And in a country as hot as this. For sure there is no equivalent laws to the UK on being legally obliged to provide water. How these people all live to be 90 I will never know!
No idea how France compares, but I would prepare for the worst in terms of water being supplied.