You can use "sv_ignoregrenaderadio 1" to turn off grenade radio and "bot_chatter off" to turn off bot radio commands, but I don't think you can actually turn off all radio commands.

(NOTE: I found that by typing "find radio" in console. It gave me all the console commands that have to do with the radio.)

Use "sv_vote_issue_kick_allowed 0" to disallow vote kicks.

(NOTE: I found that typing "find vote" in console.)