Thank god I read to the bottom of this thread, because the early posts made me so angry and upset I couldn't believe I was on MN. "Pseudo mother'? "Just a stepmother"?? 
And so many people who quite simply don't get the issues involved with lesbian parenting.
First off it needs saying that we do not know nearly enough about what happened in this case to be able to pronounce who is in the wrong.
It is NOT easy to create an alternative family within current legal and social structures, that's for sure. Sounds like the mothers tried to set up an arrangement with a male friend in which they would be primary parents but he would be known and involved. That is exactly my family set-up. It is what many lesbians try to do because they don't want to risk their dc growing up distressed that they can't know anything about their paternal lineage. It is a damn hard thing to get right. You need to find a man who is mature, loving and responsible enough to be involved in the child's life - and also sensitive, flexible and self-aware enough to be able to anticipate how his feelings may alter after birth and be able to handle that.
You can set this up, you can write a contract (we did), but it is not legally enforceable. (It is not clear whether these parents had a written contract.) Our dd's dad insisted he wanted to be on the birth certificate and therefore adoption is not possible for us. We felt it best for our dd to have her father named, and to give what we consider very reasonable access (a full weekend every fortnight, often pops in on the other weekend, some holidays). Frankly, she loves him but would rather see him less (she is a little homebody) but we make her go because it's the deal and we want their relationship to flourish. But it is NOT the same as being a child who had two primary parents, one of whom then moved out. He has NEVER been her primary parent and she is much closer to her non-biological mother, who has no legal relationship to her. This makes us feel very vulnerable but we are convinced it is best for our child, who loves all her three parents.
It is completely insulting to basically say to lesbian parents that the only two options we should be entitled to are anonymous sperm donation or being the same as divorced heterosexuals. Those who say 'sexuality is irrelevant' are wrong, actually. This is about lesbians (and, usually, gay men) trying to find new ways to parent and be in families. It is tough and risky and demands great flexibility and generosity and ability to understand the child's real needs. There have been many times when I could have cheerfully throttled my dd's father, but he is loving and responsible and has great integrity, and I have great respect for him and for the promises we made before conception. Equally, I am certain that he often finds it difficult and painful to accept his role as third parent, but he knows his daughter benefits hugely from a strong and secure primary family unit.
Who knows what went on with this family? It is easy to focus on the access hours, but isn't the real issue that he is trying to assert himself as a primary, though non-resident, parent? If my dd's dad did that I would feel furious and betrayed, and would fight him all the way. On the other hand, it is possible that the mothers made promises (explicit or implicit) about his involvement that they are now finding inconvenient to honour, and gradually freezing him out - which is just not on. Lesbians and gay men need to be especially honourable in these situations, and try to avoid resorting to a legal system that does not recognise or understand our families or our lives.