Tintin as a Character
The thing about Tintin is that despite being in the protagonist role, is a very evil man. He frequently abuses animals, is responsible for the deaths of two men, is a close-minded bigot and is more than a little arrogant. Now, some would see this as a flaw in the storytelling but assuming it was intentional, it might mean that Hergé gave credit to his audience, and expected them to think critically about the ever-changing definitions of "good" and "evil". If it was a conscious choice, then it makes Tintin all the more interesting as a character and as a story.
By giving his protagonist such soft, gentle and friendly features he is able to provide contrast to the horrible things that Tintin himself does. Tintin is also a layered character, as he is not all evil or all good. He does save lives and he does take them, he also does morally gray things that rely on the interpretation of the reader.
In conclusion, I don't think that Tintin was the product of a small-minded bigot like many have claimed. Perhaps his work has poorly aged because of the times, but I want to think that Hergé was a thoughtful man who wanted to make his readers think about his work, and not have his work think for them.