So what you mean is that the Boltzmann brain can have no causally-connected beliefs about Obama, not no beliefs-as-everyone-else-uses-the-word about Obama. Fine, but your original statement and your clarification still gratuitously repurpose a word with a conventional meaning in a manner that will be actively misleading to the reader, and doing this is very bad practice.
So what you mean is that the Boltzmann brain can have no causally-connected beliefs about Obama, not no beliefs-as-everyone-else-uses-the-word about Obama. Fine, but your original statement and your clarification still gratuitously repurpose a word with a conventional meaning in a manner that will be actively misleading to the reader, and doing this is very bad practice.