Did the offence get edited out of some post?
I'm assuming the infraction comes from: Member rules
Seems to me, that regardless of how one tries to justify it, calling someone "ignorant" can easily fail that rule.3. Community Rules: We are a community of adults. Minimum age to join these forums is eighteen, but they're read by people of all ages, so watch your language. One account per person -- do not use anyone else's account nor allow anyone else to use your account. Treat others with dignity and respect, whether you feel they deserve it or not. Attack the post, not the person -- personal attacks of any kind will not be tolerated. Learn and use the Taxonomy of Logical Fallacies. As this is a science forum, keep discussions on religion and politics in the background, and keep it respectful i.e. no racism, sexism, or religion-ism. If your pet theory goes against the mainstream, post it in that section. Respect the privacy of others – do not share PM's and e-mails on the forum. If someone breaks these rules, report their post using the post report function. Feel free to edit your posts for spelling and grammar, but once you've posted, do not go back and delete your posts. For significant content changes, simply create a new post.
(For example, a person may be "overweight" so it's "factual" to call that person "fat". However, depending on context and tone, that's easily taken (or given) as an insult.)
Seems a fair infraction (though with the disclaimer I've not seen the actual post). People don't get banned 'round here often.