It’s not racist. People accuse others of that term too flippantly. It is ignorant though.
Language changes a great deal over time, and slurs are no exception. What is a completely inoffensive label at some point can be a slur later on. What is a mild insult in one area can be much more severe somewhere else. Sometimes what was a slur can be reclaimed and become acceptable, even positive. But that can also depend on who is saying it and other contextual details. I don’t know anything about “k!wifarms” but I wouldn’t assume malicious intent without more information.
That example looks much like the No True Scotsman fallacy, since a word is redefined later to exclude what would be exceptions to their claim based on an added qualification. Person A also made Person B get the evidence to refute their claim rather than fulfilling the burden of proof themselves. I know it’s not a formal debate or anything, but even so, bad faith arguments are just rude. Just own the mistake and say “you’re right, I was only thinking of first world countries/liberal democracies/developed nations/whatever”.
I second this. I am in a similar position as OP and now I donate to a fund through GiveWell (which is used by many people engaged in EA) directly since the start of this year. If you want your money to do the most good, look into them. They research and audit all kinds of charities and publish their findings on their site.