You ask: “Oh people of the Book! Why are you hiding verses of Lord Allah while Allah is a Witness upon whatever you are doing?”.
Today, the Arabic Quran reading Fujjar are falsely boasting and claiming that they are the people of the Book. They are leading a life according to their whims with a concept that the Three-Time-Knower Lord is not observing them and they will not have to answer about their worldly life before Him on the Day of Judgment. By forgetting Adhikr they have become worthless people as told in verses 25: 17-18. The Fujjar are denoted as the worst creatures not due to not hearing and talking about the Arabic Quran, but due to not hearing and talking about Adhikr as explained in verse 8: 22. See explanation 2: 254-255; 3: 81 and 25: 33-34.