Not so sure I’d want to base decisions on a survey based on self-reported data, either.
Self-reported data is not the most reliable data. People forget, people want to appear more likeable than they are, people lie, people aren’t very self-aware… hence self-reported data isn’t generally terribly reliable. It would be much more interesting to see actual hiring results rather than what employers want others to think they hire based on. Those same employers would also almost certainly report they are completely unbiased regarding race and gender of applicants, but we know based on surveys that use actual results - not self-reporting - that this is not the case.
Logically it makes no sense that employers for most industries give no preference to offering internships or hiring interns from less or more prestigious programs. It makes more sense that the students from a program that is perceived to be strong would have an advantage in being offered more and better internships or more likely to be hired for internships that are open to all students. And that would be part of the start of the cumulative impact of going to a more well-regarded program, whether the self-reported surveys show that or not.