How can Wikipedia prevent liars and miscreants from suppressing the truth?

Someone on facebook posted, with apparent approval, a link to the an announcement DOCTORS’ GROUP VOTES TO OPPOSE VACCINE MANDATES. The doctor’s group is the Association of American Physicians and Surgeons (AARP). It’s webpages (including the announcement above) look official.

But the wikipedia article on AAPS says

The Association of American Physicians and Surgeons (AAPS) is a politically conservative non-profit association founded in 1943 to “fight socialized medicine and to fight the government takeover of medicine.”^[1][2] The group was reported to have approximately 4,000 members in 2005, and 5,000 in 2014.^[3][4][5] Notable members include Ron Paul and John Cooksey.^[6] Ron Paul’s son, Rand Paul, was a member for over two decades until his election to the U.S. Senate.^[7] The executive director is Jane Orient, an internist and a member of the Oregon Institute of Science and Medicine. The AAPS motto, “omnia pro aegroto” is Latin for “all for the patient.”^[8] AAPS also publishes the Journal of American Physicians and Surgeons (formerly known as the Medical Sentinel).

The association is generally recognized as politically conservative or ultra-conservative, and its publication advocates a range of scientifically discredited theories, including the belief that HIV does not cause AIDS, that being gay reduces life expectancy, that there is a link between abortion and breast cancer, and that there are links between autism and vaccinations.

I commend wikipedia for being able to maintain that entry in the face of the expected efforts by supporters of AAPS to edit away the truth.  How do they manage to do it?