A lot of arguments can be seen as sensible until one realizes they were pushed by people with a hidden agenda. It's often just the motte part of motte-and-bailey arguments.
That's why there are people (eg. in Europe) who aggressively promote secularism, and many agree with that, until you find out they belong to some hateful anti-islam organization. And that's why some people put science into question, like, how can we be sure of anything, which is defensible from an epistemological standpoint, until you discover they are creationists.
So you want to be careful before giving random people the benefit of the doubt.