In this Sutra the Buddha address concerns of those (the Kalamas) who are told to accept teachings with out proof. According to the Kalamas, there were many people who would pass through their village and teaching about their beliefs and critize others who had taught before them. Confused by this, the Kalamas questioned Buddha about how they should take the teaching of those who passed through. The Buddha taught not to accept anyones teachings just because this person said it is so. He doesn't mean for people to distrust any religions, just educate yourself, experience things for yourself, and make your own judgement about what practices are true for you. You can only know what is right for you. I think this is one reason Buddhist do not proselyze like other religions. Buddhist wait for a student or other person to question them about the beliefs and pracitces of Buddhism. We don't seek to convert anyone. We will teach those who ask, encourage them to find out more about Buddhism on their own before taking Refuge Vows. I have below a list of what not to go upon when accepting teachings. This what I tell myself every time I start studding a new teaching.

Do not go upon what has been acquired by the words of others.
Do not go upon rumors.
Do not go upon what is written as scared words.
Do not go upon tradition.
Do not go upon what is surmised or assumed.
Do not go upon an axiom.
Do not go upon false and illogical thought.
Do not go upon unfavorable influences towards an idea.
Do not go upon someone else’s apparent abilities.
Do not go upon the esteem of a teacher.

Accept a teaching when you know that the teachings are positive, they will not hurt others, that they will only help and not hinder ones journey in any way and when you know that those who have dwelled on these words will have only gained in positive merit.

The Buddha began his talk by saying to the Kalamas:

" It is proper for you, Kalamas, to doubt, to be uncertain; uncertainty has arisen in you about what is doubtful. Come, Kalamas. Do not go upon what has been acquired by repeated hearing; nor upon tradition; nor upon rumor; nor upon what is in a scripture; nor upon surmise; nor upon an axiom; nor upon specious reasoning; nor upon a bias towards a notion that has been pondered over; nor upon another's seeming ability; nor upon the consideration, 'The monk is our teacher.' Kalamas, when you yourselves know: 'These things are bad; these things are blamable; these things are censured by the wise; undertaken and observed, these things lead to harm and ill,' abandon them."

Reading the Kalama Sutra can help anyone studying Buddhism by teaching them that you must practice, study, question what you study, then practice some more. There are some very good interpretations of the Sutra too that will make you think.