I must be thick because I certainly don't understand the statement "they are arguing that these images should NOT have alt text as it doesn't add anything to the disability screen reader as the image text would be repetitive with the text on the page. "
No, I haven't run into this problem before. Perhaps they're referring to situations where alt tags just get stuffed with keywords. Image alt tags shouldn't just repeat the text on the page or act as a repository for keywords, although that's often what you see. Image alt tags should accurately describe the image first, use keywords second and where it makes sense.
So, for example, this page has an alt tag coded for the little blue button above that depicts Roger, the company mascot (<img <span class="html-tag">alt</img <span>="Roger_blue_square"). The text "Roger blue square" doesn't appear anywhere else on the page. (Well I guess it does now!) It's a bit succinct - first time visitors might have a heard time understanding what the image represents - but it is accurate and isn't just stuffed with "Moz Q&A Community" keywords.
I'm waiting for the day when Google decides to start penalizing folks for doing what you've described above.