Well, Buzz, I don't think anyone is saying she can't.
Cadpat is asking whether her own (negative) emotional response is justified, and, further, whether she should take the step of expressing her negative response to Macleans.
I don't think anyone is posting saying "Darn it, this opinion must be obliterated, never expressed again, and all memory of it wiped from the earth."
And, seriously, how might that be done?
There is, of course, a whole issue about power and representation. I suspect Cadpat has picked up on the disproportionate weighting in the forums of representation gifted to Cadpat and Thingy (sorry, forgotten her name). Thingy's opinion is represented as a book, and as an academice book, and will be widely circulated, as an academic treatise, ie raised above mere "opinion". Cadpat is posting on an internet forum, and thinking of writing a letter to the magazine. The two opinions do not carry equal weight.
Off at a tangent, isn't it interesting that someone is publishing an academic book about this? What sort of strange cultural currents is it picking up on?
Clearly, to bf, to not bf is a heated issue out in the world. I looked up the book on-line, and it doesn't seem to have a cultural-studies type chapter dealing with that objectively, which I would have expected from an academic, rather than a polemic/mass-market book.