Yes, I noted that, too. Classic projection, IMHO.
I've also wondered whether Brenda, perhaps below the conscious threshhold, has her suspicions about Damon's possible guilt. Why else would she choose that particular thing to show Pierce (the "Daddy please love me" excerpt from Danielle's journal hidden in the nightstand drawer)? Brenda, yanked back by Damon and the prospect of her own perceived culpability in trusting him, and not wanting to come to terms with the "evil" possibility that Damon had to do with Danielle's demise, joins in the vilification of Pierce -- "Yes, HE is evil, not what I fear about the man I depend upon." You get it.
There are also other little clues that Brenda has some doubts about Damon. For example, her testimony that that the dog "busted her nose" by running into Damon's leg (euphemism for "Damon kicked the dog"), full knowing that most folks consider that a man who would harm a pet is also capable of harming a child...