What's happening is that lowercase "sentence case" titles have become more popular and normalized so repeated exposure to that style can cause a subconscious heuristic of "Capitalized letter signifies a Brand Name or Proper Noun". You can try to advise people not to assume that but it doesn't change the type of "sentence case" titles people are now repeatedly exposed to.
The New York Times still uses "Title Case" but a lot of other newspapers switched to lowercase sentence case. Washington Post switched in 2009. And Los Angeles Times, The Boston Globe, the Chicago Tribune, the San Francisco Chronicle, Philadelphia Inquirer, etc all followed.
Other popular websites with lowercase titles include Vox, ArsTechnica, TechCrunch, etc.
