Aight TMC writer here.
Basically, it boils down to a lot of lingering animosity to Goonswarm/CFC/Imperium. I will try to make it a little easier to understand.
First off, Goons are understood to be the 'bad guys' in space. We pretty much fell right into that label. An ironfisted dictator that is the leader of a group that models itself after the 40k Imperium of Man? Yeah that's us. Goons are also known for their nature as blob warfare specialists, so we aren't always fun to fight but when someone drops the ball on us it is impressive. There is a lot of bad blood between many members of Eve Online and the Imperium, with many reasons that differ from person to person. From being a fucking pain to fight, to dislike of the leader of them, Goons are pretty well disliked across Eve, and also well liked as well for occasional cunning and the way that they came into power.
Second, The Mittani, who often goes by Mittens, or his IRL name Alex Gianturco, is the leader of the Imperium. He is also the owner of a website called themittani.com, or TMC for short.
TMC has been accused of real money trading/transfer, or RMT. Basically, cash directly to ISK. This mainly has to do with ad revenue. The writers themselves are paid with ISK directly for all the Eve related articles they write. This is totally fine. And it isn't news that the ISK payment we recieve as writers comes from ingame sources such as taxes, ratting, moon goo, etc. This has been the norm for a while.
TMC also has ad revenue, which helps keep the site running, pay editors, and line Mittens pockets. This isn't illegal and for all intents and purposes it is totally fine by CCP and I assume the laws of the place it operates.
TMC has had the opportunity to have a book written about the Fountain War, which was a conflict that the Imperium took part in. There are concerns that this book will not reflect all sides of the conflict accurate or put Goons in a spotlight. Jeff Edwards is writing this book for TMC. This is being funded by a kickstarter.
Combine all this and you basically have lingering animosity exploding into rage directed at the Imperium, with most of it directed towards Mittens.
I can answer any other questions if I can.