Brown is either stupid or trying to intentionally deflect. No one has every said Seth Rich did any kind of “attack”. All he had to do is to copy files to a memory stick, any computer user can do that. Especially if someone told him where to find the files in question.
Rich’s patriotism is the very thing that would have motivated him to expose the DNC treachery.
The most plausible explanation is that someone (sysadmin) spotted the file accesses while during routine auditing and alerted someone who then took action. If Rich had to use elevated permissions to access the file that would have made it even easier to detect.
One such person would be the IT director, e.g. Brown. If so there’s your motive for him to lie and spin about Rich.
Seth Richs’ actions were not motivated by patriotism, Seth Rich was a true follower of Bernie Sanders. His actions were motivated by Clinton stealing the nomination from Sanders.
Seth Rich should not have died like this, but please don’t make him into a patriot.