In the case of Mangione, some stats proved his support reached the real world. If I remember correctly, something like 43% of <30s approved of his crime.
31% positive for those under 45, 8% positive for those above 45.
41% negative for those under 45, 77% negative for those above 45.
Not the majority, even for younger people. And remember, this is just U.S. opinion; people in other countries might view this differently (likely even more negatively).
Edit: look at the photos of the people… AI generated perhaps?