It's not terribly surprising to me that a third-party mod that requires the use of a special kernelspace program only works on Windows.

FWIW, Valve doesn't require use of that system for tournament play and is of the opinion that VAC is sufficient to run a Counterstrike tournament. [0][1]

[0] <https://github.com/ValveSoftware/counter-strike_rules_and_re...>

[1] See section 3.4 of the license you have to agree to to run an official tournament <https://store.steampowered.com/tourney/limited_license>