FlyerTalk is heavily populated with whiners and crybabies. These are people who seem to expect absolute perfection from all service industries -- even though such an expectation is both unrealistic and hypocritical.
And the complaints are not just about UA -- you see the whining and screaming throughout the site. Oftentimes, people will switch loyalties to a different airline or hotel chain, only to start b*tching about their new pick (in some cases almost instantly -- the honeymoon period can be very short).