On one side of the coin, it logically makes sense that ATS systems would help recruiters pare down the list. I'd assume there is some auto-rejection happening, but how sensitive is it (getting rid of clearly unqualified candidates vs. rejecting marginal candidates vs. actually qualified but still rejected due to not being ATS-friendly)? You here about job postings getting thousands of applicants and it seems like it would be impossible to go through those by hand.
On the other side, I see lots of posts from recruiters saying ATS's do not judge resumes and everything is done by the recruiter. These posts seem to be very skeptical of anything saying it will optimize your resume for ATS's because there is no need to actually do that.
Would love more perspective on this issue.