No one made such a claim. Latin is still used as a working language of the Catholic Church is because it is a dead language, meaning the definition of its words are fixed, helping to communicate precise theological terms and concepts.
I like to refer to the Latin fetishists as "Jeromites" because if it weren't for St. Jerome, there would be no scripture in Latin.
Sure, what about those of us Catholics who do NOT use the Latin rite or Latin in any way, shape or form.
I don't oppose Latin in the Latin Church, but I do have a problem with the idea that Latin=Catholic. The Latin language contributed to the schism with the Greek East because it is NOT as precise of a language as Greek to dealing with abstract theological terms. The filioque is a prime example of how the Latin language mangled theology.
Why not Church Slavonic, Syriac, Classical Armenian, Byzantine Greek or Ge'ez?