Mo has been the Yankee closer for about 15 years or so. I would think that in at least 10-12 there has be a closer in the AL equal to or better than Mo. Rivera's greatness is in his year after year after year etc of domination along with his sterling, but by no means unblemished post season record.
Since 97 most teams, at one time or many times, had to find a closer for the following year, not so in New York. We knew we had one of the best. Hard to find a safety net like that.
Of course Soriano deserves credit for what he's done this year. Doubt anyone could have done better under the circumstances. But some folks just don't warm up to him. Human nature, no big deal. (In fact there are some people who, unbelieveably, don't like me. Including my wife occasionally. I chalk it up to envy!)