My friend is quite insistent they are not. I've utterly given up trying to convince him, given every single evidence I've looked at confirmed my opinion, but he contends that every shred of evidence actually confirms HIS opinion, and concluded by comparing me to a flat-earther (!).
Some of the evidence is about as reliable as a rubber I-beam: Dictionary.com redirects a search for "remediate" to "mediate", which he pointedly ignored, and the difference in definition formulation in OED ("To put right, reform (a state of things); to rectify, make good." vs. "To provide a remedy for, redress, counteract; to take remedial action against."; both entries are pretty recent AFAICT, though the "remediate" one seems to me to merge legalistic and general elements) has more to do with their efforts to avoid repetitiveness in similar words than a difference in meaning (several of the examples are very similar).
Anyway, I'm throwing myself to the wolves: am I making an utter idiotic asshole of myself here?