Aren’t we all blasphemers?

What is a blasphemy? By what I have read it is saying something against GOD, religion or a religious figure which may be considered insulting or disrespectful. In some countries Blasphemy is punishable by death if you happen to insult the Prophet of Islam, religious figures and religious books (name the Holy book of the Muslims-The Koran or Quran) especially in Pakistan and other Muslim countries. By this definition everybody in this world seems to be blasphemer as we think that our religion or even sect is right and all the others are wrong and in the heat of the argument start insulting the other religion and then there becomes no difference between any of us. And it is not just in the heat of the argument but inadvertently or by choice we do blasphemous stuff almost every day and then go about the day like nothing has happened. I was reading an article by a person long time ago and he raised an excellent issue that states that one person's blasphemy may not be the other person blasphemy and vice versa and started to think that he is absolute right about it. And further more blasphemous laws in some countries and especially and particularly in Pakistan have been used by some Muslims to instigate and settle their differences. For example somebody will say that he/she somebody insulting the Prophet of Islam or damaging the book of Islam and the police has to arrest the person and in the meanwhile this allegation false or not becomes a rally cry for the people of the area and they are ready to kill the alleged blasphemer without a hint of investigation if the allegation is true or not.