He writes (in reference to Ackerman and others): "These people are irrelevant on the Middle East." He is not saying to ignore any "bad advice" he might get from these folks, rather he is saying that Obama should not even be talking to any of them in the first place.
And just to clarify, Ackerman does not oppose Obama's approach to Israel and does not do whatever AIPAC tells him to do. Ackerman supports Obama's policies with respect to Israel and the Middle East. I'm not sure why you would think otherwise.
Some examples:
Ackerman rips critics of Obama on engagement: "Shameless nonsense!"
Calling the last administration's record in the Middle East a "spectacular disaster," Rep. Gary Ackerman (D-N.Y.), chairman of the House Middle East subcommittee, came out guns blazing today to ridicule hawks who criticize the Obama administration's efforts to engage Syria as appeasement.
http://www.politico.com/blogs/laurarozen/0410/Ackerman_rips_critics_of_Obama_on_engagement_Shameless_nonsense_.htmlRep Ackerman Clarifies Position: Supports Peace, Supports Obama, Supports Settlement Freeze
Well, whatever the Jewish press and Politico thought (or hoped) Ackerman’s views might be, today’s statement is clear: Chairman Ackerman is not saying families shouldn’t grow, or that people should not have babies, but he is saying that settlement construction must stop, period. This is the view that the Chairman, clearly and unequivocally, has articulated today. It is a welcome and important clarification from Chairman Ackerman.
http://yglesias.thinkprogress.org/archives/2009/06/rep-ackerman-clarifies-position-supports-peace-supports-obama-supports-settlement-freeze.phpMatthew Yglesias, noted liberal blogger, said the following about Ackerman:
I did an item critical of Ackerman based on that Politico report, so I feel a special obligation to correct the record. Ackerman, as a Jewish representative from a district with many Jewish constituents, has—like Rep Robert Wexler (D-FL)—an especially important role to play as an advocate for a progressive approach to the region. He should be the kind of member who signals to other members that it’s kosher to be against settlement expansion.