The line is indeed, fuzzy. The basic definition of a disorder is very much dependent on context, because in general it requires that the behavior or thought pattern is causing distress or danger to the patient or those around them. There are many facets of the human mind which have a substantial variation among the population, where some range is adaptive to certain situations and some part becomes a problem, and where exactly that flips will depend on the individual and the context they are in. But I think it's unhelpful to claim that because this line is contextual, it means there isn't really a problem. It's a problem because that individual is in that context (and often it's preferable to address the behaviour or thought patterns than the context), and there are individuals where it would be a problem in basically any context.