Use of the word "should" is most often in the form of advice or a recommendation. It is weaker in form than "must" or "have to."
However, the word has taken on more ominous tones, especially within our Christian circles.
We might preface a statement with "I think," and add "you should...", but the harm is already done.
Regardless of how we cut it, giving an opinion about how one "should" behave or believe is tantamount to judging--especially if that advice or opinion was not asked for.