While under legal orders to covertly obtain as much information about an adversary group, it is only logical to assume the persona and adopt the background of one of their own. It is equally logical to exaggerate certain facts or omit others as required to accomplish your assigned task.
See, by misleading (lying to) the Maquis, Tuvok was being as Vulcan as he could be
See, by misleading (lying to) the Maquis, Tuvok was being as Vulcan as he could be