Tourists and neutrals are fine, I've been to be plenty of games as a neutral, but I wouldn't be cheering when the away team scored if I was sat in the home seats. That's the same across Europe, not just England, so we before we flog ourselves to death about being terrible fans, it's just the nature of club football. Is it logical, no, of course it isn't, but that's how it is.
Interestingly, at national level this doesn't seem to be as prevalent, is it because the type of fan that travels around the world has a different mindset to club fans?