"Because tanking doesn't tip the playing field against anyone else." If this isn't the dumbest post of the year, it's in the conversation. It at least bumps tanking good/trade rape bad down one spot on the list.
Tanking, in fact, tips the playing field against EVERYONE else. As MikeT noted, doing it all season is less harmful. In a world with a MWR tankers get to the minimum and then lose as many as they can the rest of the way, impacting who makes playoffs. I can't think of anything that does MORE to tip the playing field. It tips the playing field against everyone who tries to be competitive each season, and diminishes the quality of draft picks for the other owners. You are correct that everyone has the right to run his team how he wants. But everyone else has an equal right to not want such owners in their worlds. To make a distinction among tanking and trade rape is silly. Both are harmful and make worlds harder to fill. Both show a lack of respect for the other 31 owners in a world. A good world can block trade rape through vetoes and educating noobs. A good world can do little about tanking other than hope the owner doesn't renew in time.
And yes, it matters how a team becomes dominant. Without tanking or trade rape, it is nigh impossible to build a 115-120-win team. If someone builds a consistent 100-game winner honestly, other owners should offer congratulations. If someone does it by tanking and trade rape (or collecting cash from aliases), not so much. There's a reason almost every private world as MWR, the reason is that tanking takes enjoyment out of the game for the majority that don't do it.
I look forward to whatever straw man you can concoct to argue against points I'm not making here.