While I agree there’s danger in generalizing your feelings as proof positive of bigotry/racism/whatever, I think there’s also danger on the other end of being too subjective. There have to be things and people that are not just offensive to me, or that I deem to be bad, but that simply are offensive or bad; delving too far into reluctance to call a spade a spade can act as tacit acceptance of what should be unacceptable. To use your metaphor, you may like chocolate when you’re young and not like it when you’re older, but we all have to be able to agree that a Big Mac left out in the sun for a week is not edible.
And personally, I think the problem is that we’ve got a bunch of people who are relatively poorly calibrated on this metric, to where they err, as you accused the author here of doing, on the side of assuming everyone they disagree with is morally or ethically flawed, or where they err in assuming that all people finding flaws are whiners, and the only people who are actually flawed are those who proudly state that they are so (i.e., that the only people who are actually racist are the ones in the white hoods). Neither of those things is true, but as long as 90% or so of us believe one or the other, there’s not going to be an end to the partisanship and divisiveness.