That is not so; the CC0 explicitly states that patent and trademark rights are not waived.
Contrast that with, say, the Two-Clause BSD which says "[r]edistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met [...]".
Since trademark and patent rights are not mentioned, then these words mean that even if the purveyor of the software holds patents and/or trademarks, your redistribution and use are permitted. I.e. it appears that a patent and trademark grant is implied if a patent holder puts something under the two-clause BSD. Or at least you have a ghost of a chance to argue it in court.
Not so with the CC0, which spells out that you don't have permission to use any patents and trademarks in the work.
Contrast that with, say, the Two-Clause BSD which says "[r]edistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met [...]".
Since trademark and patent rights are not mentioned, then these words mean that even if the purveyor of the software holds patents and/or trademarks, your redistribution and use are permitted. I.e. it appears that a patent and trademark grant is implied if a patent holder puts something under the two-clause BSD. Or at least you have a ghost of a chance to argue it in court.
Not so with the CC0, which spells out that you don't have permission to use any patents and trademarks in the work.