If you have disinfected water available, that's great. Hypothetically, suppose I was marooned somewhere and had (a) a small amount of drinkable water I'd carried with me; (b) some found water that I'd consider too contaminated to drink; and (c) fresh urine. I suspect that the urine would be a better choice for cleaning wounds than the found water. It'd be nice to use the carried water to rinse out the urine at the end, but I wouldn't use it for that if I felt I needed it for drinking.

If I had the means to purify the found water, that changes things. The point is, urine isn't always the worst choice.