"The police protected you and there were courts of law." - So this is addressed to someone coming to live in the US from another country (I suppose - I don't know the full context...) In some countries - especially with authoritan governments (I can think of a few...) the citizens cannot rely on the police or the legal system to deal with them or judge with them fairly, based on an established legal framework. On the contrary the police may take actions based on political considerations or self interest (e.g. to get bribes). There are many examples of such practices: for example, I have heard of cases where a woman is raped, but it is sometimes the woman who is punished - or the rapists receive no, or very leniant sentences. Here the police might suggest that the woman is at fault for "encouraging" the men/ man - or that she is in fact lying. Another example, I met a man who, in conversation with a friend at a cafe, used an insult when talking abour a minister of his country. Someone overheard. The police were called. The man was arrested. It is a long story, but in the end the man and his family were forced to flee their country and now live permanently in another country. I could go on, but you see, the implication in the context of your sentence is that in America, you can rely on the police and the courts of law to protect the citizens and treat them fairly. That seems to be the suggestion in the extract you have given. However, as I don't know the full context of the dialogue, it could be that the speaker is in fact being ironic or sarcastic - i.e. he may believe that the US is not at all the "paradise" referred in the first line. After all, bad things can happen in any country.

and this sentence what meaning? The police protected you and there were courts of law.

courts of law, where there is a judge and jury. For example, if the police arrest you because you committed a crime, you have to go before a judge in a (law) court and he or she decides if you are guilty or innocent