"For people who are deaf, have hearing loss, or are deaf-blind, this includes providing a qualified notetaker; a qualified sign language interpreter, oral interpreter, cued-speech interpreter, or tactile interpreter; real-time captioning; written materials; or a printed script of a stock speech (such as given on a museum or historic house tour). A “qualified” interpreter means someone who is able to interpret effectively, accurately, and impartially, both receptively (i.e., understanding what the person with the disability is saying) and expressively (i.e., having the skill needed to convey information back to that person) using any necessary specialized vocabulary."
Source: https://www.ada.gov/effective-comm.htm
They could have complied by hiring an interpreter or even simply writing captions for the lecture, but they decided to violate the law instead.
Also,
> Don't be the person who burns down someone else's house just because you don't have one.
is absolutely disgusting. The ADA exists because, as a society, we decided to make life accessible for disabled people. One day you'll get hurt, and you'll learn how important reasonable accommodations are.