I have no idea if that's what's happening in your case, but I have noticed that allistics tend to behave like they know something when I think they don't. I think it's a matter of how we define knowing something. For me, knowing something means that I am fairly certain that I understand the details, connections, and am confident in how I obtained the knowledge. For allistics, it's more about sharing that they have heard about it and that people agree with them. Additionally, while autistics may feel comfortable openly sharing that they don't know something, allistics see this as a sort of weakness or embarrassment. Since knowing could mean your guess, your friends may be asking you for your opinion, not your certain knowledge, so they could feel that you are withholding it. Additionally, since knowledge is socially constructed for allistics, you not engaging in the topic prevents them from creating knowledge, you're deciding to not engage in their concern, and they feel disregarded and vulnerable not having "knowledge" on whatever they're concerned about, whether validly rooted in objective reality or socially constructed.
Disclaimer: These are generalities and every person, allistic or not, has their individual idiosyncrasies.