Well, dictionary shmictionary. No lexicographer wants you to lie down and roll over just because the phrase you use is not recorded in his or her latest tome. If we say advocate for, the dictionaries will recognize, soon enough, that the intransitive form ("she advocates for abuse victims") is standard -- and in this case doing useful work, not just padding out the transitive verb.
And advocate for is not some bizarre new aberration; the OED calls it obsolete, but gives citations from the mid-17th to the late 19th century, the last from the language scholar Fitzedward Hall: "I am not going to advocate for this sense of actual." And Google's Ngram viewer shows "advocated for" rising steadily since around 1840, so maybe the OED editors weren't as observant as they might have been.
I doubt, though, that people who dislike the revival of advocate for give a damn whether it's "officially" transitive or intransitive; I think they connect it with social-worker jargon from the touchy-feely era, and despise it for class reasons. Yes, it's true (as I noted in a column* four years ago) that advocate for sometimes shows up where advocate alone might be more appropriate (and elegant). But (as I wrote then)
advocate will hardly be the first switch-hitting verb. Do you baby-sit the twins, or baby-sit for them? Shop [Filene's] Basement, or shop at the Basement? Graduate college, or graduate from college? A century ago, when approve of was new, Ambrose Bierce tsk-tsked: "There is no sense in making approve an intransitive verb." [I wonder how he would have liked the British transitive agree: "Heineken UK have agreed a contract extension."]This isn't the first time advocate has attracted critics. The OED quotes a 1789 letter from Ben Franklin to Noah Webster (happy birthday, Noah!) complaining of several new verbs (as he thought) based on nouns, including advocate. Milton and Pepys and Burke had used the word, but Franklin wasn't having it. "If you should happen to be of my opinion with respect to these innovations," he wrote, "you will use your authority in reprobating them."
But Webster (whatever his private opinion) recorded the facts: advocate was a verb, like it or not. And any minute now, his heirs at Merriam-Webster -- hi, Peter! -- are going to notice that it's also an intransitive verb, and add that description to the record. Because we're the boss of dictionaries, not the other way around.
*Probably behind a paywall, but I can't tell for sure.