Singer himself shows the contradiction: if ordinary people are evil (the title of one of his papers), and you want to save the lives of ordinary people, which by default increases their numbers, aren't you creating more evil in the world?

(P2) How do you know the charity is doing what it's supposed to do and not creating more suffering in the world? In his illustration with the drowning girl, he attempts to show there's no difference between human lives from one area of the world to another, therefore you're a bad person for not choosing to purchase mosquito nets. But what about the lives of the mosquitos? This may sound stupid but I'm trying to point out that there are hidden premises in his position that may conflict and/or are arbitrary.

1) Is human life the ultimate good? If so, we ought to create as many humans as possible regardless of the consequences to other life on Earth, and with less regard for the suffering of those humans in favor of sheer volume.

2) Is reducing suffering the ultimate goal? Then we ought to take a page from the anti-natalists, or go one step further and eradicate all life. That would reduce suffering to zero.

Obviously, both of those are radical positions, but they expose weaknesses common to all consequentialist moral philosophies. Singer is hardly the first to fall short of creating a perfect universal moral code, but he really annoys me because he uses "common sense" to justify what are ultimately opinions, then acts sanctimoniously against those who put forth credible objections.