TBH I don't really understand why these comments made by "breastfeeding advocates" would offend or upset someone unless they already had a hang up about their decision to FF. If you are confident in your decision then why would these statements matter?
I think because it's annoying that people have these misconceptions & feel qualified to say them. I am totally at ease (and a little bit righteous) about my breastfeeding, but I still get narky when people start telling me when to wean, how to feed solids, when to feed solids, how much to feed, etc. It really bugs me. Not because be I have any doubt in what I'm doing, but because clearly other people have so much doubt, that they need to tell me.

And I think it's fair to be annoyed by that.