Shielding form kinetic attacks requires immobilizing kinetic assaults on their person but consider that these Borg are on starship's moving speeds that would transform them into "jam" if they were not protected/enveloped by the artificial gravity field, inertial dampening field and structural integrity field...
Maybe if they wanted to stand still, they could be entirely resistant to physical trauma, but an attempt at motion against these conflicting forces would be conflictive to say the least if each Borg was generating their own kinetic field whose intensity and density would again be reliant on how many Borg were standing beside one another or working with surfaces outside themselves.
Borg on a planet however should be fine? As fine as Worf in his wild west gunfight durning a fist full of Datas.
Maybe if they wanted to stand still, they could be entirely resistant to physical trauma, but an attempt at motion against these conflicting forces would be conflictive to say the least if each Borg was generating their own kinetic field whose intensity and density would again be reliant on how many Borg were standing beside one another or working with surfaces outside themselves.
Borg on a planet however should be fine? As fine as Worf in his wild west gunfight durning a fist full of Datas.