The idea that authors can get blacklisted for sharing their thoughts online is generally treated as a myth. But it does serve a useful purpose in that you sometimes find small presses, usually start ups, who do believe in it. And these are publishers to avoid.
Case in point, Gemstone Romance.
A poster by the name of Anne noted that "Horrified Press" was not looking particularly promising as "newish startup without publishing/editing experience". And that they seemed to be associated with another startup, Gemstone Romance.
Graeme Reynolds replied with more information about Horrified press and "Gemstone Romance is a separate entity, which I am funding and am
applying the Horrific Tales business model to, but is being run by
Charlotte Courtney. I am simply providing financial, technical and
business support to the venture. It will use a different editorial team..."
He then added: "Also, a word of advice to Anne, who wrote this post. Probably not the
best move to make when trying to get business from a publisher. Consider
yourself off the shortlist for Gemstone Romance. Best of luck in
whatever you do next."
Which both seriously undermines his claim of total editorial independence between Horrified and Gemstone, and is some grade-A unprofessional passive aggressive bullshit. Time will tell if he decides to try and backfill that hole or just keeps digging.