Scientists, many educated and respected scientists, also said the boundary of the universe was only the Milky Way. The people that questioned that premise were also said to lack the ability to understand scientific evidence.This is true.
What is also true, is if the question being asked is based on no evidence. Science works by the peer reviewed method. Evidence against Science does not include a person's lack of ability to understand scientific evidence.
The Earth is not flat, you can question that all day long but if you cannot prove it with evidence then you fall into the category of a belief system and can be ignored.