Everyone there asks that Beruria's point seems incorrect. Tanach is filled with examples of sinners- Chot'im- being referred to as sins- Chata'im. One good example is our parsha, where Aharon was commanded to gather the incense plates of the supporters of Korach, who were killed by divine retribution for their rebellion, and they are referred to as Chata'tim. את מחתות החטאים האלה בנפשותם.
The Nesivos in his Nachlas Yaakov (and Emes L'Yaakov and Iyei Hayam) says two answers to this question.
One of the reasons I like the second answer better is that the first answer doesn't work well in the language of the Gemara. According to that pshat, Beruria was saying that the passuk in Tehillim was indeed a curse against recidivist sinners, but there people were not like that. The problem is that she said that this explains the passuk ועוד שפיל לסיפיה דקרא ורשעים עוד אינם כיון דיתמו חטאים ורשעים עוד אינם אלא בעי רחמי עלויהו דלהדרו בתשובה ורשעים עוד אינם , "look at the end of the passuk! There will no longer be wicked people- because Chata'im came to an end, the result is there will no longer be wicked people. Pray for them that they do Teshuva." According to the first answer, the passuk is not talking about people for whom you pray, it's talking about people whom you curse.
- The word חטאים can mean people who have sinned, and it can mean veteran sinners. Rav Meir's neighbors were people who sinned, the congregation of Korach were sinners.
- Also, the Akeida that not all sinners are equally culpable. Some people are faced with physical or emotional or cultural drives that are far harder to resist than those that others face. They're all judged for their sins, but you don't throw the book at the ones that are nebach resha'im. As the Baal Ha'Akeidah puts it, דינא רבא ודינא זוטא איכא בינייהו. Does this support Rav Dessler's "נקודת הבחירה"? I don't know.