A much better quote would be "Be considerate of the fact that every rule has exceptions". Whenever I hear this quote, or anything like it, it is because someone is making the fallacious claim that exceptions disprove the rule. They will always deny that they are making that claim, but under scrutiny one can always prove that it is an inherent part of whatever argument they are making.

The idea that you can disprove a fact by pointing out an exception is a fundamental part of leftist ideology. Quotes like this are used to introduce kids to that logical fallacy.