Not to defend the blasphemy law but there is a difference here. One is a “sinner” and one is a “blasphemer”, sinner is someone who believes (or says so) in God but acts on his own wishes (while disobeying God) but someone who ridicules religion/religious text (regardless of his/her belief) that’s blasphemy. This is just like people who believe in the laws of the land but don’t follow it whenever they can or actually commit a crime, they are called criminals but someone who doesn’t believe in the laws of the land and acts against the country will be called outlaw/traitor (?) or some other term.