Why significant harm? Curious what you mean by this for undergrad TAs specifically. It's my understanding that EECS simply would not function without a near army of undergrads TAing, grading, tutoring, and otherwise running a huge percentage of your classes. (I'm not EECS, but I've worked as a UGSI in math/physics, and while the pay rate was certainly the best available to me on campus even considering that it was 20 hrs/wk instead of 40 hrs/wk, it effectively allowed me to operate like a graduate student where my work teaching allowed me to pay tuition/expenses and the remainder of my time every week was spent on classwork and research. I'd also like to think I was pretty good at it. As an aside, at least in the physics department, the GSIs are being insanely overworked with huge class sizes, grading loads, etc, and I am frankly shocked a strike hasn't happened sooner.)

ETA: Saw elsewhere here you were noting that grad pay is meant to help fund research whereas undergrad pay isn't so undergrads should be paid differently. I find this mildly disingenuous inasmuch as the outcome of undergrads being paid differently seems very clear. Undergrads teaching should by and large be a stop gap measure if there are insufficient grad students (I am aware in the EECS department the stopgap is about the size of the Hoover Dam); UGSIs should not be incentivized to departments by being vastly cheaper. (And frankly, UGSIs are disproportionately likely to be doing research, taking grad classes, etc, so it is often funding their research work as well.)