I didn't say that you were implying that B&E should only be used for text, but that you were hinting that it only looks good in a certain way. You were showing him what 'good B&E looks like' after saying he did it wrong, and that when people don't do it right, it looks "horrid". I don't think there's a right and wrong for this because it depends on personal preference.
But no it's not rude to share your opinion, I just think the manner in which you did was. You could have easily showed him the examples without all the coarseness. It's off-putting for people just getting into designing, and I thought someone who posted about wanting to help beginners would be more encouraging and less passive aggressive.
Also:
How are people supposed to practice and experiment when people act as if they committed a crime? I'm not trying to be rude about it, but you can see why I mentioned what I did.