I, too, have done the “all communication is manipulative”, but in the same way as one would do a bar trick:
all communication is manipulative, for any words I say/write that you perceive instantly manipulate (as in the physical manner / modifying state) your thoughts, and this is done so without you requesting I do so
it’s a handy stunt with which to drive an argument about a few parts of communication, rhetoric, etc. because it gives a kinda good handle on some meta without getting too deep into things
(although there was one of my friends who really, really hated the framing)
fwiw this link didn’t jump me to a specific reply (if you meant to highlight a particular one)