Online poker sites that are legitimate and have passed through third-party scrutiny are NOT rigged. But some players won't believe this, and feel they are being cheated over issues such as: Too many bad beats. More pots being won by depositing players (to encourage new players)
Bots are computer programs designed to play poker without human oversight. Bots are illegal and unethical to use. Unlike their human counterparts, bots never succumb to tilt, they never misplay a hand, and they never get tired of playing. Bots can play on and on indefinitely, making money over the long run.