And then what? They're just normal, melee-only zombies? A weaker demolisher at best?
Why would you want to nerf what is (almost) the only ranged enemy in the game? Just for realism? You're entitled to your opinion, but I believe gameplay must take priority over "realism," which I put in scare quotes because we're talking about zombie abilities.
I guess the cop's attack animation could be lengthened so he's shown munching on some grass before he spits. That animation is already janky - he seems to not face the direction he's spitting.