I agree with J0NE5YG4MING to some extent. That kind of thing does tend to snowball. A lot of players just get really upset when they get killed through tactics they don't completely understand, then call hacks and get pissed at you because you want to do a thorough investigation before swinging the ban hammer. Of course, they're also offended you didn't just take their word for it since they are obviously experts on the game mechanics. It's rough being an objective admin. And some admins just get sick of dealing with all of it when they find out how much work actually has to go into maintaining a fair server and keeping it populated. Which brings me to my next point...
DDOS attacks. Most servers aren't on dedicated metal. They share IPs with a handful of other game servers. When a DDOS attack hits your server's shared IP, it takes all of the other game server instances down with it. It really takes the wind out of your sails when you've worked really hard as an admin to get your server population up to have it brought down because you, (or some other admin with the same IP) banned the wrong kid who gets pissed and initiates an attack. By the time the attack is over, you've lost all the players you worked so hard to attract. Some admins just give up after that. Rebuilding population isn't easy.
About the ddos , you couldn't of said it better. This is what happened to my server. It sucks bad. I can't get the server passed 40 people.
It really took a drain on us because of the hard work we put into the server keeping it fair and clean.
It's a shame.