When did the software community get so bad at handling legitimate critique?
"You should really be ashamed of yourself for doing this" is an inappropriate response for basically anything but kicking puppies.
That sounds somewhat specious, lying about what you support in your cost calculation library is a pretty big oof. It's hard to rank it versus kicking puppys, but, I don't think we have to stack-rank bad things to figure out if it's okay to call out unethical behavior.