If I gave away free pork sandwiches, would I be allowed to call them “vegan”, merely because I didn’t charge for them?

This is not about the money.

Bad analogy doesn't help with your argument.

The source code is open, different people have different opinion about the definition of "open source".

if someone calls a pork sandwich "vegan", that's objectively false. Not the case for the concept of open source because the definition is murky and I refuse to follow some authority's definition of what open source is.

You’re jumping from argument to argument. You explicitly argued that since it was free, nobody should be able to claim anything wrong with how it was presented.

Now you’re instead claiming that the term “open source” was perfectly justified, since the definition is “murky”.

So which is it? Either the term “open source” is fitting, in which case it should not matter if they charge for it or not, or it’s only OK since they don’t charge for it.