bot_minplayers automatically adds/kicks bots if the number of humans on the server is less than bot_minplayers. For example if it's set to 2 and there is 1 human, there will be 1 bot.
I think 2 is the best setting for pub.
I set this to 2 on your server, Laser, but you set it back to 6. I joined a Korri game and it was filled with annoying faggot bots repeatedly suicide jumping into the lava every second. I really don't think pubbers enjoy playing with that.
2 is good because it is enough to keep the server from being empty, but it's not enough to be annoying to people who actually want to play. Maybe others enjoy having legions of useless bots on the server at all times. I don't know. Here's a poll.