Walsh spoke against same-sex marriage, abortion and transgender people.
Speakers addressed the science and perceptions behind the virus.
Derek Black publicly condemned the ideology in 2013.
The former national intelligence director will speak at Xfinity Center in December.
Del. Eric Luedtke teaches public policy at UMD in the fall, and represents Maryland's 14th district in the spring.
The two frontrunners are a woman and a black man.